Cephalometry without complex dedicated postprocessing in an oriented magnetic resonance imaging dataset: a pilot study.

OBJECTIVES: Magnetic resonance imaging (MRI) enables a 3D-volume-imaging without ionizing radiation. Therefore, it was the aim of this study to present a post-processing-free method for cephalometric analysis of a MRI-dataset and to examine whether there is a significant difference between cephalometric analysis of conventional 2D cephalograms and MRI scans. METHODS: One MRI scan each was performed on three cadaver heads using a 3T-MR-scanner. Cephalometric analysis was conducted directly on the 3D dataset. All reference points were projected onto a virtual sagittal plane that was perpendicular to the Frankfort horizontal plane. Double-sided points were averaged. Cephalometric angles were measured from the projected points. Results were compared with cephalometric measurements on conventional lateral cephalometric radiographs (LCRs). The cephalometric analysis was performed by five raters. RESULTS: 390-angle measurements were obtained. The inter-rater reliability was high [intraclass correlation coefficients (ICCs) ≥ 0.74 for all angles]. Differences between the measurements on the cephalograms and MRI scans ranged between -0.91° (-1.88°, 0.07°) and 0.97° (-0.63°, 2.57°) on average and were equivalent with respect to a margin of [-2°, 2°] in all angles except L1-Me-Tgo (Bonferroni-Holm-corrected P < 0.05 in all angles except L1-Me-Tgo). The best match was found for the SNA angle. CONCLUSION: The clinical comparability of the MRI- and LCR-based cephalometry could be stated. Using MRI in orthodontics would reduce radiation exposure and the risk of stochastic radiation damage, which is of importance especially in younger patients.

Determination of the mesio-distal tooth width via 3D imaging techniques with and without ionizing radiation: CBCT, MSCT, and µCT versus MRI.

Objective: The purpose of this study was to estimate the feasibility and accuracy of mesio-distal width measurements with magnetic resonance imaging (MRI) in comparison to conventional 3D imaging techniques [multi-slice CT (MSCT), cone-beam CT (CBCT), and µCT]. The measured values of the tooth widths were compared to each other to estimate the amount of radiation necessary to enable orthodontic diagnostics. Material and Methods: Two pig skulls were measured with MSCT, CBCT, µCT, and MRI. Three different judges were asked to determine the mesio-distal tooth width of 14 teeth in 2D tomographic images and in 3D segmented images via a virtual ruler in every imaging dataset. Results: Approximately 19% (27/140) of all test points in 2D tomographic slice images and 12% (17/140) of the test points in 3D segmented images showed a significant difference (P ≤ 0.05). The largest significant difference was 1.6mm (P < 0.001). There were fewer significant differences in the measurement of the tooth germs than in erupted teeth. Conclusions: Measurement of tooth width by MRI seems to be clinically equivalent to the conventional techniques (CBCT and MSCT). Tooth germs are better illustrated than erupted teeth on MRI. Three-dimensional segmented images offer only a slight advantage over 2D tomographic slice images. MRI, which avoids radiation, is particularly appealing in adolescents if these data can be corroborated in further studies.

Comparative study of image quality and radiation dose of cone beam and low-dose multislice computed tomography--an in-vitro investigation.

OBJECTIVES: The aim of this study was to evaluate the image quality and dose exposition of different cone-beam computed tomography (CBCT) and low-dose multislice spiral CT (MSCT) scanners. MATERIALS AND METHODS: A human cadaver head was examined with three MSCT and five CBCT scanners. The radiation dose was measured using an Alderson RANDO phantom. Standard protocols were used to obtain the CBCT data. For the MSCT devices, the tube voltage and tube current were modified to obtain acceptable image quality while keeping the radiation dose as low as possible. The image quality of MSCT and CBCT devices was determined by examining the enamel-dentin and dentin-pulp interface and the periodontal ligament space of 22 teeth. RESULTS: Inter- and intra-observer agreement was found for the different groups of raters. CBCT systems were rated superior to MSCT devices in terms of image quality for all dental structures. The differences in image quality among the studied CBCT and MSCT scanner groups did not turn out to be significant but were significant between CBCT and MSCT devices. The organ dose varied considerably between the different CBCT and MSCT devices. The differences concerning the organ dose were notably pronounced in the area of the eye lens. CONCLUSIONS: The tested devices exhibited significant differences with respect to the organ dose. The variance was particularly pronounced in the CBCT devices. With a dose exposition equal or lower than the CBCT, the image quality in the MSCT devices was judged to be significantly worse.

Three-dimensional volume tomographic study of the imaging accuracy of impacted teeth: MSCT and CBCT comparison--an in vitro study.

The aim of this study was to analyze the imaging accuracy of cone beam computed tomography (CBCT) data sets compared with multislice spiral computed tomography (MSCT) data sets in determining the exact mesiodistal width of unerupted porcine tooth germs and to compare the radiologically obtained results of width measurements with the actual mesiodistal dimension of the tooth germs. In MSCT and CBCT data sets, the largest diameter of 24 tooth germs was determined with the aid of the mesial and distal contact points. The reference method used was mesiodistal width measurement using sliding callipers after the tooth germs had been osteotomized. Accuracy and precision were ascertained with difference plots and a one-way model II analysis of variance with random effects. Analysis of accuracy revealed marked differences between the measuring methods in the difference plot: slightly higher mean values were measured by MSCT and markedly lower values by CBCT than by the reference method (calliper); the mean deviation was significantly greater for CBCT. The width of the confidence interval in the comparison of CBCT versus clinical measurements is more than 4 times higher than in the comparison of MSCT versus clinical values. Precision analysis found that repeatability was twice as high with CBCT as with clinical measurement, whereas MSCT and clinical measurement differed only slightly. The mesiodistal width of displaced teeth can be determined by MSCT but also by CBCT. MSCT is superior to CBCT in determining tooth width; the difference was statistically significant (P = 0.05).

Individualized erlanger KS-impression trays for infants with cleft lip and palate.

OBJECTIVE: The use of individualized impression trays is required when taking impressions of the maxilla in infants with cleft lip and palate. Custom trays made of plastic such as polymethylmethacrylate, as well as generic, full-arch infant metal trays, have been used up to now. Given the increasing incidence of infectious diseases, the ability to sterilize impression trays for infants with cleft lip and palate is mandatory. Polymethylmethacrylate impression trays are altered in shape and consistency when autoclaved during the sterilization process. Therefore, they have to be fabricated afresh at regular intervals. METHODS: Based on modified mold patterns of the available plastic trays, 44 pieces were sorted into four groups of 11 trays in ascending order of size. On these plaster casts, which served as the male part of the template, a 1-mm layer of sheet wax was applied. An optimized ergonomic wax handle was then fitted to the wax plate. Realization in a chromium-cobalt-molybdenum alloy was performed according to the lost wax principle. CONCLUSIONS: The sterilizable Erlangen KS-Impression tray (Erlanger KS-Abformlöffel®) is now available in 11 sizes for each of four basic forms. They meet current hygiene guidelines. They can be recommended for routine use when taking impressions in infants with any form of cleft lip and palate without complications.

Repeatability and reproducibility of landmarks--a three-dimensional computed tomography study.

The aim of this study was to investigate the repeatability and reproducibility of the placement of anthropological cephalometric landmarks on three-dimensional computed tomography (3D CT) cranial reconstructions derived from volume data sets. In addition, the influence of the observer's experience on the repeatability of landmark setting was also explored. Twenty patients without any craniofacial deformity (11 females and 9 males; age range 6.1-16 years) were selected retrospectively from CT volume data sets already available from 695 patients of Dental Clinic 3, Orthodontics of Erlangen University Hospital. The CT examination was performed with the SOMATOM Sensation64 (Siemens AG Medical Solutions, Erlangen, Germany). The program VoXim6.1 (IVS Solutions AG, Chemnitz, Germany) was used for 3D reconstruction of the volume data sets. A total of 28 landmarks were examined in the skeleton module of the program VoXim6.1. The randomly sorted data sets were analysed by two orthodontists and two postgraduate students. Each data set was analysed twice by each observer at an interval of 3 weeks. The analysis of variance regarding random effects was used to calculate the intraobserver and interobserver components of standard deviation (SD) of depiction of individual landmarks as measures of repeatability and reproducibility, respectively. Median intraserial SD and interserial SD of 0.46 mm (range: 0.14-2.00 mm) and 0.20 mm (range: 0.02-2.47 mm), respectively, were obtained depending on the landmark and plane. This study included systematic analysis of extreme values (outliers) in the assessment of the quality of measurements obtained. Descriptive statistics revealed qualitative differences in the depiction of different landmarks. The landmarks nasion and infradentale revealed a minor SD in all three spatial coordinates with the smallest SD for infradentale (SD = 0.18 mm) in the transverse plane. However, no systematic trend was identified with regard to the influence of the observer's level of experience affecting the repeatability of landmark positioning. Thus, the repeatability and reproducibility of placements of landmarks with 3D CT were found to be acceptable for a majority of anatomical positions.

Impact of specific orthodontic parameters on the oral health-related quality of life in children and adolescents : A prospective interdisciplinary, multicentre, cohort study.

PURPOSE: The aim of the present study was to analyse the impact of specific orthodontic findings on oral health-related quality of life (OHRQoL) when taking into consideration age and psychological factors in children and adolescents. METHODS: In all, 250 children and adolescents with an indication for orthodontic diagnostics were recruited using a multicentre study design. Using validated and internationally acknowledged questionnaires, we assessed OHRQoL, health-related quality of life (HRQoL), self-esteem and behavioural problems. We also examined a selection of specific orthodontic findings using photos, model casts and cephalometric analyses, and investigated the impact of these parameters on OHRQoL using simple linear regression analyses. Thereafter, we added all the significant specific orthodontic and psychological parameters to a multiple linear regression model using a stepwise forwards selection procedure. RESULTS: We were able to identify different specific orthodontic findings that have a significant impact on OHRQoL. These were the type of lip closure, the position of the chin, the Little-index of the upper jaw, the overjet, the overbite and the ANB angle. Moreover, we were able to demonstrate that psychological and some specific orthodontic parameters have a significant impact on OHRQoL. CONCLUSION: Specific orthodontic findings have a significant impact on patients' perceived OHRQoL. Further longitudinal studies are required to investigate whether the treatment and correction of these malocclusions also improve the OHRQoL of children and adolescents.

A new generation of self-etching adhesives: comparison with traditional acid etch technique.

OBJECTIVE: The aim of this study was to determine the shear bond strength (SBS), etching pattern and depth, and debonding performance of several market-leading, self-etching (SE) adhesives primarily used in restorative dentistry (iBond, Clearfil S(3) Bond, Clearfil Protect Bond, AdheSE, XenoIII), two experimental self-etching adhesives (exp. Bond 1, exp. Bond 2) and one experimental self-etching cement (SE Zement) used with and without prior phosphoric acid-etching, and to compare them to an orthodontic self-etching product (Transbond Plus SE Primer) and to traditional acid-etch technique (Transbond XT Primer, phosphoric acid) MATERIALS AND METHODS: All adhesives were applied on pumiced and embedded bovine incisors following the manufacturers' instructions. Then one bracket each (coated with Transbond XT composite) was bonded (n = 20). Transbond XT was polymerized for 20 s from the incisal and gingival sides using a halogen device positioned at a constant 5 mm from and a 45 degrees angle to the specimen. The specimens were stored in distilled water for 24 h at 37 degrees C before measuring SBS. The ARI (adhesive remnant index) for all specimens was determined from the sheared-off brackets of each. After conditioning, the surface texture was morphologically evaluated from scanning electron microscope (SEM) images, while the etching depth was determined using a confocal laser-scanning microscope (CLSM). All groups were tested for normal distribution and analyzed by applying ANOVA, Kruskal-Wallis or the t test. In addition, a Bonferroni correction was used. RESULTS: The median values of the SBS tests were: SE Zement 3.0 MPa, SE Zement preceded by phosphoric acid etching 11.2 MPa, experimental bond 1: 7.4 MPa, experimental bond 2: 5.6 MPa, iBond 8.1 MPa, Clearfil S(3) Bond 14.1 MPa, Clearfil Protect Bond 16.6 MPa, Clearfil SE Bond 15.9 MPa, AdheSE 16.0 MPa, XenoIII 16.1 MPa, Transbond SE Primer 20.7 MPa, acid-etching+Transbond XT Primer 21.0 MPa. With the exception of iBond, we observed no significant differences among the self-etching adhesives used in Restorative Dentistry or in comparison to the Transbond Plus SE Primer. No significant differences were apparent even when compared to the Transbond XT Primer after phosphoric acid-etching. Both experimental bonding agents and SE Zement without acid etching performed significantly worse than the products mentioned above, failing to demonstrate sufficient adhesive strength. SEM examination revealed less distinctive enamel-etching patterns for self-etching products than for phosphoric acid-etching. CLSM analysis revealed etching depths between 0.5 and 20 microm depending on the product. When self-etching products were used, less residual composite remained on the enamel surface than after phosphoric acid-etching. CONCLUSIONS: All the adhesives tested are suitable for bonding orthodontic brackets and to reduce the risk of enamel fracture while minimizing etching depth, which in turns means less conditioning-related enamel loss. More development is needed to improve the etching performance of both experimental bonding agents and SE Zement.

Three-dimensional analysis of facial symmetry in cleft lip and palate patients using optical surface data.

AIM: Presentation of a new technique to determine the plane of symmetry of a face, and to assess the degree of facial symmetry in patients with unilateral cleft lip and palate based on three-dimensional (3D) optical surface data. PATIENTS AND METHODS: After having determined a plane of symmetry according to optical 3D facial surface data, we identified differences in landmarks, the surface areas of the upper lip vermilion and nostrils and virtual volumes of the midface, nose and upper lip for cleft and unaffected sides in forty 10-year-old patients suffering from complete unilateral cleft lip, alveolus and palate. The children had undergone lip repair via the Tennison-Randall technique and had received subsequent orthodontic treatment (but not secondary osteoplasty). RESULTS: Statistically significant differences were apparent between cleft and non-cleft sides in terms of the nasal landmarks, nostril angle and virtual volume of the nose. The upper lip was symmetrical when cleft and non-cleft sides were compared. CONCLUSIONS: This new technique of symmetry analysis reveals that the noses of 10-year-old patients with complete unilateral cleft lip and palate who had not undergone revisional surgery present a measurable and significant degree of asymmetry, while the upper lip is symmetrical as a consequence of interdisciplinary treatment by orthodontists and oral and maxillofacial surgeons. Further 3D analyses on larger numbers of patients will allow more comprehensive and consistent analysis of the potential and limitations of various surgical and conservative methods so as to identify those techniques with the best outcome in terms of facial symmetry.

Prevalence of temporomandibular disorders in patients with Hashimoto thyroiditis.

OBJECTIVES: Autoimmune thyroid disease (AITD), also known as Hashimoto thyroiditis (HT), is a degenerative inflammatory disease with high prevalence among women and has been associated with fibromyalgia and widespread chronic pain. The goal was to determine the frequency of temporomandibular disorders (TMD) in patients with HT. METHODS: In all, 119 women (age 19-60 years) were divided into a study (52 women diagnosed with HT) and a control (67 healthy individuals, of which 15 were excluded) group. Serum concentrations of thyroid-stimulating hormone (TSH), free triiodothyronine (fT3), free thyroxine (fT4), anti-thyroglobulin (Tg) and anti-thyroid peroxidase (TPO) antibody levels were measured. The temporomandibular jaw and muscles were examined using the German Society of Functional Diagnostics and Therapy guidelines. The Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) was used to assess TMD. Standardized questionnaires, incorporating epidemiological criteria, state and treatment of the thyroid disease, Helkimo Index (HI), and Fonseca Anamnestic Index (FAI), were filled out by all patients. RESULTS: The two groups did not differ in terms of demographic parameters or mandibular jaw mobility. Significantly higher levels of anti-TPO and anti-Tg were attested in all subjects of the HT group. Markedly elevated prevalence of TMD was found in the HT group. Muscle pain and stiffness were found in 45 (86.5%) subjects of the HT group (p < 0.001), of whom 33 (63.4%) also had disc displacement with reposition (p < 0.001). Whereas 50% of the control group showed no TMD symptoms, all subjects in the HT group had symptoms. CONCLUSIONS: A significantly elevated prevalence of TMD was found in patients with HT. Thus, patients with TMD who do not respond to therapy should be referred for thyroid diagnostic workup.

Oculoauriculovertebral spectrum and maxillary sinus volumes : CT-based comparative evaluation.

OBJECTIVES: To evaluate, by comparing maxillary sinus volumes, how asymmetries related to oculoauriculovertebral spectrum (OAVS) affect upper-jaw development. METHODS: From pre-existing multislice spiral computed tomography (MSCT) datasets, we selected 20 cases of 11 female and 9 male patients aged 6.1-24 years who were clinically and radiographically symmetrical (group 1) plus 20 cases of 8 female and 12 male patients aged 5.7-23.9 years who had OAVS (group 2). After three-dimensional reconstruction of the datasets, the volumes of the left and right maxillary sinuses were calculated and compared based on patient groups and based on the sides affected or unaffected by OAVS. To this end, the OAVS patients were subdivided into a group in whom both external acoustic pores were radiographically present (group 2a) and a group in whom the pore on the affected side was congenitally missing (group 2b). RESULTS: Intrarater reliability was very high (0.997). Significantly larger volumes of the maxillary sinuses, amounting to a mean of 13.4 ml, were observed in the control group than in the asymmetric OAVS groups where the volumes averaged 9.8 ml or 10.3 ml, respectively (p = 0.03). No statistically significant differences in sinus volumes were found between the two OAVS groups (p = 0.557) and between the sides affected or unaffected by the OAVS (p = 0.8311 in group 2a and 0.4961 in group 2b). CONCLUSIONS: Overall, we found the volumes of both maxillary sinuses to be somewhat smaller in the asymmetric patients than in the symmetric control group. This might indicate that OAVS was associated with a mild generalized hypoplasia of the maxilla, but significantly different sinus volumes were not seen between the affected and unaffected sides.

Correlation between oral health-related quality of life and orthodontic treatment need in children and adolescents-a prospective interdisciplinary multicentre cohort study.

PURPOSE: Oral health-related quality of life (OHRQoL) is a construct for assessing the self-perceived oral health of patients. The aim of this study was to investigate the correlation between OHRQoL and orthodontic treatment need in consideration of demographic and psychological factors. PATIENTS AND METHODS: This multicentre study included 250 patients with an indication for orthodontic diagnostics. In cooperation with the Institute of Clinical Psychology at the University of Würzburg, validated and internationally acknowledged questionnaires were selected to assess OHRQoL (COHIP-G19) and health-related quality of life (HRQOL). Self-esteem and behavioural problems were taken into consideration as possible psychological factors. Orthodontic treatment need was assessed using the Index of Orthodontic Treatment Need-Dental Health Component (IOTN-DHC), the Index of Orthodontic Treatment Need-Aesthetic Component (IOTN-AC) and the Dental Aesthetic Index (DAI). Possible significant correlations between the collected parameters and OHRQoL were evaluated by means of linear regression analysis. RESULTS: Objective orthodontic treatment need (IOTN-DHC and DAI) was significantly correlated with OHRQoL. Further factors significantly influencing OHRQoL in children and adolescents were age, HRQOL, self-esteem and behavioural problems. CONCLUSIONS: Objective orthodontic treatment need significantly influences OHRQoL in children and adolescents. Further studies are required to investigate if OHRQoL may be improved by correcting misaligned teeth and jaws.

Oro-dental pathologies in acromegaly.

PURPOSE: Oro-dental pathologies (ODP) such as enlargement of the tongue, mandibular prognathism, and spaced teeth are characteristic features of acromegaly. Their frequency of occurrence during the course of the disease is largely unresolved. Purpose of this study was to assess ODP and oro-dental treatments in patients with acromegaly with regard to the length of the diagnostic process, tumor histology, and quality of life (QoL). METHODS: Single-center retrospective survey study using questionnaires on dental symptoms, diagnostic process, and treatment in patients with acromegaly operated on a growth hormone-secreting pituitary adenoma. The association between ODP and QoL was assessed using the Short-Form 36 (SF-36) Health Survey. RESULTS: 145/314 patients completed the questionnaires. 80.7% were affected by any ODP, most frequently enlargement of the tongue (57.9%), spaced teeth (42.8%), mandibular growth (24.1%), and mandibular prognathism (22.1%). ODP were significantly more frequent in patients with sparsely vs. densely granulated adenomas (p = 0.045). Early diagnosis within 2 years was associated with significantly fewer ODP than later diagnosis (68.5 vs. 87.2%, p = 0.009). Treatments included dental crowns (16.6%), dental bridges (12.4%), dental implants (9.7%), dental prostheses (3.4%), orthodontal (i.e., braces, 6.9%), and surgical correction of the teeth (2.1%). Physical QoL was significantly lower in patients with ODP than in those without (p = 0.014). CONCLUSION: In our large series of patients, four of five patients were affected by ODP at any time during the course of the disease. The results highlight the importance of early identification and treatment of oro-dental problems in patients with acromegaly as hallmarks of the disease.

Variance of landmarks in digital evaluations: comparison between CT-based and conventional digital lateral cephalometric radiographs.

AIM: The aim of this study was to examine whether bony, dental and soft tissue landmarks could be placed in CT-based lateral cephalograms with the same precision as in conventional digital lateral cephalograms. MATERIALS AND METHODS: Nine patients without craniofacial dysplasia (2 female, 7 male, aged 12.8-32.3) who had undergone a lateral cephalogram and CT examination within an interval of a maximum of 6.5 months were selected in retrospect. The lateral cephalograms were done with the ORTHOPHOS Plus DS Ceph, and the CT examination with the SOMATOM Sensation 16 or 64 scanner. The CT-based cephalograms were generated with the VoXim 4.3 program based on axial CT reconstructions in the bone window. The cephalograms were analyzed using the Onyx Ceph 2.7 software by 2 orthodontists and 5 postgraduate students, each cephalogram being examined five times by each examiner on different days. Statistics were compiled with SPSS 13.0 and 14.0 based on the deviation from the individual mean value of each landmark. RESULTS: The descriptive statistics showed in the conventional cephalogram, averaged over all 61 landmarks, a mean quartile range of on average 0.62 mm in the horizontal and 0.67 mm in the vertical axes. The CT-based cephalograms ranged between 0.64 mm horizontally and 0.74 mm vertically. The statistics comparing the two types of images with the Wilcoxon test for paired samples showed no significant difference. CONCLUSION: When a CT scan is necessary for assessment of complex craniofacial dysplasias, an orthodontic-specific diagnosis is possible without having to resort to conventional X-rays of the skull. The data from this study demonstrate that it is possible to construct a cephalogram from CT data, which can be analyzed in the same way as a conventional cephalogram provided that the CT's field of view is large enough.

Enamel Demineralization during Fixed Orthodontic Treatment - Incidence and Correlation to Various Oral-hygiene Parameters.

OBJECTIVE: To investigate the incidence of white spot lesions (WSLs) around brackets and molar bands during orthodontic therapy, and establish whether a correlation to indices of dental and gingival health, fluoride application and oral hygiene could be demonstrated. PATIENTS AND METHODS: Fifty-three patients with fixed orthodontic appliances were included at random in this study at the Department of Orthodontics of Erlangen-Nuremberg University. Dental health (DMFS), plaque index, papillary bleeding index, sulcus probing depth (SPD), gingival recession (GR), clinical attachment level (as sum of SPD and GR), oral hygiene, and fluoride use were evaluated. WSLs were graded from intraoral photographs taken before and after treatment. RESULTS: 97.5% of teeth before and 73.6% after treatment were free of WSLs. Of all teeth, 24.9% developed new WSLs or a rise in their number. New or more numerous WSLs were more common in upper and lower premolars (34.4%) and front teeth (28.1%) than molars (11.8%). WSL incidence during therapy correlated with clinical attachment level, and the oral hygiene and fluoride-use scores. CONCLUSIONS: Despite improvements in materials and preventive efforts, orthodontic treatment continues to carry the considerable risk of enamel demineralization. Each patient's prophylactic efforts, including fluoride use, are of paramount importance in preventing WSLs.

Effects of enamel sealing on shear bond strength and the adhesive remnant index : Study of three fluoride-releasing adhesives in combination with metal and ceramic brackets.

OBJECTIVES: Selected combinations of materials were used to create tooth-adhesive-bracket complexes to evaluate shear bond strength (SBS) and the adhesive remnant index (ARI) with regard to enamel sealing. METHODS: Four adhesive systems also appropriate for use as enamel sealants were combined with four bracket types, resulting in 16 adhesive-bracket combinations, each of which was tested on 15 permanent bovine incisors. Sealant-adhesives included two recently introduced fluoride-releasing systems (Riva bond LC® and go!®), one established primer (Opal® Seal™), and one commonly used adhesive as control (Transbond™ XT). Brackets included two metal (discovery® by Dentaurum and Sprint®) and two ceramic (discovery® pearl and GLAM®) systems. After embedding the bovine teeth, bonding the brackets to their surface, and storing the resultant samples as per DIN 13990-2 with modifications, an SBS test was performed by applying the shear force directly at the bracket base in an incisocervical direction. Then the ARI scores were determined. RESULTS: Discovery® + Transbond™ XT yielded the highest (47.2 MPa) and GLAM® + go!® the lowest (17.0 MPa) mean SBS values. Significant differences (p < 0.0001) were found between metal and ceramic brackets of the same manufacturers (Dentaurum and Forestadent). Our ratings of the failure modes upon debonding predominantly yielded ARI 0 or 1. The high SBS values and low ARI scores observed with discovery® + Transbond XT™ were reflected in a high rate of enamel fracture, which occurred on 11 of the 15 tooth specimens in this group. CONCLUSIONS: All sealant-bracket combinations were found to yield levels of SBS adequate for clinical application. SBS values and ARI scores varied significantly depending on which sealant-brackets were used.

Assessment of facial soft-tissue profiles based on lateral photographs versus three-dimensional face scans.

OBJECTIVES: The purpose of this study was to compare two-dimensional (2D) lateral photographs versus three-dimensional (3D) face scans in analyzing facial profiles using Schwarz's concept of the jaw profile field (JPF) in its original 2D and in a modified 3D version. In addition, the distribution of the facial profile types described by Schwarz were examined. MATERIALS AND METHODS: Of 75 adult volunteers recruited specifically for this study, we obtained both photographs (Nikon D 300S; Nikon, Düsseldorf, Germany) and scans (FaceSCAN3D Scientific Photolab 60 Hz; 3D-Shape, Erlangen, Germany) in a standardized setting. Four raters analyzed the pertinent measurements using image analysis software (Onyx Ceph 3; Image Instruments, Chemnitz, Germany). Statistical analysis was conducted using the R suite environment (v. 3.2.1; R Foundation for Statistical Computing, Vienna, Austria). RESULTS: Intraobserver reliability was substantial for two raters (κ = 0.61-0.8), moderate for one (κ = 0.41-0.60), and almost perfect for one (κ = 0.81-1.00). As for interobserver reliability, we observed moderate agreement between the two basic technologies tested, but internal agreement was only moderate even within the 2D view modes (average κ = 0.51) versus almost perfect within the 3D view modes (κ = 0.84-0.94). Forward-slanting anteface was clearly the most common (43.27%) and straight retroface the least common (0.3%) diagnosis. Only a minority of patients (18.38% of women and 16.15% of men) had straight as opposed to slanting profiles. CONCLUSIONS: Given our findings of acceptable agreement between 3D scanning and 2D lateral photography, in combination with almost perfect internal agreement between different 3D view modes, it appears useful to adapt Schwarz's method of facial profile assessment for clinical use in 3D virtual environments.

In-vitro shear bond strength of self-etching versus traditional adhesives for orthodontic luting.

OBJECTIVE: To determine the enamel shear bond strength (SBS) of various established (Resulcin Aqua Prime & Monobond N [RA], Prompt L-Pot III [PLP]) and experimental (AC-Bond [AC], AC-Bond + Desensitizer [ACD]) self-etching adhesives in comparison to fourth (Total Etch, Primer and Bonding have separate liquids; OptiBond FL [FL]) and fifth-generation (Total Etch, Primer and Bonding "One Bottle"; Excite [EX], Gluma Comfort Bond [CB]) adhesives. MATERIALS AND METHODS: All adhesives were applied on flattened human enamel surfaces following the manufacturers' instructions and light-cured using a quartz-tungsten-halogen curing device. 3.5 x 2.0 mm Tetric Ceram A2 composite cylinders were sheared off (Zwick Universal-testing-machine 1445, 1 mm/min) after thermocycling (5-55 degrees C, 5000x). Normal distribution was tested for all groups and analysis of variance was conducted. The t-test (5% level, Bonferroni-correction) was used for statistical analysis to evaluate intergroup differences. RESULTS: Shear bond strength in enamel: Resulcin Aqua Prime & Monobond N: 27.0 +/- 5.8 MPa, Prompt L-Pop III: 15.9 +/- 3.4 MPa, AC-Bond: 28.1 +/- 4.4 MPa, AC-Bond + Desensitizer: 22.2 +/- 4.1 MPa, OptiBond FL: 33.2 +/- 3.2 MPa, Excite: 30.5 +/- 5.1 MPa, Gluma Comfort Bond: 30.1 +/- 3.7 MPa. OptiBond FL demonstrated significantly higher SBS (p < 0.002) in enamel than Resulcin Aqua Prime & Monobond N, AC-Bond, AC-Bond + Desensitizer and Prompt L-Pop III. Resulcin Aqua Prime & Monobond N performed significantly better than Prompt L-Pop III, but did not differ from AC-Bond or AC-Bond + Desensitizer. The SBS values of Excite and Gluma Comfort Bond were both on the same level of significance as AC-Bond and Resulcin Aqua Prime & Monobond N, but the former showed superior results to AC-Bond + Desensitizer and Prompt L-Pop III. Prompt L-Pop III yielded significantly lower SBS-values than all the other products evaluated. CONCLUSION: Resulcin Aqua Prime & Monobond N and AC-Bond did not differ significantly from established 5th-generation products. Further in-vivo studies are required to investigate intra-oral stability and resistance against changing forces and force directions.

Shear bond strength of brackets on restorative materials: Comparison on various dental restorative materials using the universal primer Monobond® Plus.

OBJECTIVE: The purpose of this work was to analyze surfaces consisting of different restorative materials for shear bond strength (SBS) and failure patterns of metal and ceramic brackets. Bonding involved the use of a universal primer (Monobond® Plus, Ivoclar Vivadent). MATERIALS AND METHODS: Six restorative materials were tested, including one composite resin (Clearfil Majesty™ Posterior, Kuraray Noritake Dental), one glass-ceramic material (IPS Empress® Esthetic, Ivoclar Vivadent), one oxide-ceramic material (CORiTEC Zr transpa Disc, imes-icore), two base-metal alloys (remanium® star, Dentaurum; Colado® CC, Ivoclar Vivadent), and one palladium-based alloy (Callisto® 75 Pd, Ivoclar Vivadent). Bovine incisors served as controls. Both metal and ceramic brackets (discovery®/discovery® pearl; Dentaurum) were bonded to the restorative surfaces after sandblasting and pretreatment with Monobond® Plus. A setup modified from DIN 13990-2 was used for SBS testing and adhesive remnant index (ARI)-based analysis of failure patterns. RESULTS: The metal brackets showed the highest mean SBS values on the glass-ceramic material (68.61 N/mm(2)) and the composite resin (67.58 N/mm(2)) and the lowest mean SBS on one of the base-metal alloys (Colado® CC; 14.01 N/mm(2)). The ceramic brackets showed the highest mean SBS on the glass-ceramic material (63.36 N/mm(2)) and the lowest mean SBS on the palladium-based alloy (38.48 N/mm(2)). Significant differences between the metal and ceramic brackets were observed in terms of both SBS values and ARI scores (p < 0.05). Under both bracket types, fractures of the composite-resin and the glass-ceramic samples were observed upon debonding. Opaque restorative materials under metal brackets were found to involve undercuring of the adhesive. CONCLUSIONS: Monobond® Plus succeeded in generating high bond strengths of both bracket types on all restorative surfaces. Given our observations of cohesive fracture (including cases of surface avulsion) of the composite-resin and the glass-ceramic samples, we recommend against using these material combinations in clinical practice.

Three-dimensional CT evaluation of oculoauriculovertebral spectrum patients use of Katsumata's asymmetry index.

OBJECTIVES: To evaluate patients with oculoauriculovertebral spectrum (OAVS) malformations based on Katsumata's asymmetry index and to assess the usefulness of the scores thus obtained in identifying degrees and sites of asymmetry. METHODS: Multislice spiral computed tomography (MSCT) datasets of 8 female and 12 male OAVS patients aged 5.7-23.9 years were retrospectively analyzed. After three-dimensional reconstruction, central and bilateral anatomical landmarks were identified within a coordinate system defined by the sella, nasion, and dens axis. MSCT datasets of 20 clinically symmetrical patients were used to define the cutoff values for asymmetry. Based on the mean asymmetry scores and their standard deviations, the severities and sites of asymmetry were evaluated and processed for visual presentation in charts. RESULTS: Both interrater (ICC 0.7070-0.9984) and intrarater (FVU 0.0014-0.2930) reliability was very high. The calculated asymmetry scores added up to mean values and standard deviations that were higher by factors of around 1.5-2.5 than reported by Katsumata et al. More anatomical landmarks were rated as asymmetric in OAVS patients showing unilateral agenesis of an external acoustic pore than in OAVS patients without such agenesis: in the former patients, statistically significant asymmetries compared to the control group were present at the L1M (coronal pulp cavity of the lower first molar), CoP (coronoid process), and Co (condylion superius) landmarks, whereas the latter group showed such significant asymmetries at the CoP and Co landmarks. Likewise, more patients with unilateral agenesis showed asymmetries at the level of the maxilla. Highly variable severities of asymmetry were found in both subgroups of OAVS patients. CONCLUSION: Katsumata's asymmetry index can yield well-structured and illustrative views of landmark distribution, thus, suitably allowing for qualitative asymmetry evaluation of OAVS cases and identification of the skeletal regions involved.