Application of non-parametric correlations to compare the compliance of Beighton and Sachse tests in the assessment of hypermobility based on research of the fitness instructors group.

BACKGROUND: Joint hypermobility is a spectrum of symptoms associated with connective tissue disorders. The main feature is the increased range of joint mobility. Hypermobility is rarely recognised in clinical practice. The diagnosis is based on the evaluation of diagnostic tests, mainly the Beighton score. The divergence of research methods means that patients do not receive a proper diagnosis and treatment. METHODS: The study used the Beighton score and the Sachse scale. Both tests are "all-or-none-tests". Non-parametric correlations were used to assess the concordance effect. To this end, two methods were adopted, i.e., the Spearman Rank Correlation and Kendall tau Rank Correlation. The values of correlation coefficients were calculated, respectively, rho and Kendall tau. The study involved 30 women working as fitness instructors. RESULTS: Consent results of hypermobility assessment for both methods were obtained in 3 cases, while the discrepancy in the hypermobility statement concerns measurements made in 10 participants. This cursory assessment already indicates a significant differentiation of results obtained for both methods. DISCUSSION: To the best of our knowledge, there are not many studies comparing different HSD diagnostic methods. The Beighton score is the most commonly used, but the selection of only 5 joints for the examination does not show the systemic nature of hypermobility. A reliable methodology should be based not only on goniometric measurements of selected joints. CONCLUSION: The expanded correlation analysis of Beighton and Sachse hypermobility tests indicates their poor compliance. Therefore, there is a need to standardise hypermobility spectrum disorder diagnostics, which may affect the objectification and credibility of these diagnostics.

Treatment of Reticular Oral Lichen Planus with Photodynamic Therapy: A Case Series.

OBJECTIVES: The aim of the study was to clinically evaluate the efficacy of photodynamic therapy in treatment of the reticular form of oral lichen planus (OLP). MATERIALS AND METHODS: Twenty patients aged 40-76, with 40 confirmed OLP lesions in total, underwent photodynamic therapy (PDT) following the authors' own protocol, which used 5% 5-aminolevulinic acid as a photosensitizer applied two hours prior to illumination with a diode lamp emitting light at 630 nm and 300 mW. The therapy comprised of 10 weekly illumination sessions and was clinically evaluated between its completion and the end of a 12-month follow-up. RESULTS: While the baseline mean size of all 40 lesions was 2.74 ± 3.03 cm2, it was 2.97 ± 3.4 cm2 for the 30 lesions on the buccal mucosa and 2.02 ± 1.32 cm2 for the remaining 10 on the gingiva and tongue. On completion of the therapy, 37 sites improved, including 14 showing complete remission. From that point, the mean size reduction of 56.2% (1.2 ± 1.4 cm2) rose to 67.88% (0.88 ± 1.3 cm2) 12 months later. CONCLUSIONS: The results suggest that ALA-mediated photodynamic therapy was effective for the reticular form of OLP and may become an optional or complementary treatment.

Finite element analysis of the influence of porosity and pore geometry on mechanical properties of orthopaedic scaffolds.

PURPOSE: Scaffolds play a key role in regenerative medicine in the repair of injuries, defects and cancerous changes in long bones. For this reason, scaffolds should meet certain mechanobiological requirements, such as adequate porosity and pore geometry to ensure appropriate osteointegration as well as load transfer. Taking into account the most frequently used cell units, this study attempted to evaluate the porous structures of orthopaedic scaffolds in terms of their strength parameters. MATERIALS AND METHODS: Four pore geometries were selected for analyses: sphere, octagonal prism, cube and triangular prism, all with porosities of 10% up to 60%. Three different material properties were considered: Ti6Al4V alloy, CoCr alloy, 316 L steel. Strength compression simulations were carried out on 144 models, 72 structures of cell units with dimensions of 4 × 4 × 4 mm and 72 structures of scaffolds with a diameter of 16 mm and a height of 15 mm. Effective Young's modulus, as well as 0.2%, offset effective yield strength was estimated. RESULTS: Research has shown that scaffolds with bone-like strength properties should be made of Ti6Al4V alloy. The value of 40% turned out to be of the best porosity. The remaining porosities showed much lower or much higher strength parameters and were significantly different from the properties of the bones. CONCLUSIONS: The obtained data allow to indicate the most functional porous structure with Young's modulus similar to that possesses by core bone, while maintaining mechanical strength, allowing for its appropriate use in orthopaedic regenerative medicine.

The Cone Beam Computed Tomography Evaluation of Cortical Bone Plate after Piezocision-Assisted Orthodontic Upper Arch Expansion: A Case Series.

BACKGROUND: The purpose of the study was to evaluate cone beam computed tomography (CBCT) after piezocision-assisted orthodontic maxillary arch expansion. METHODS: Forty CBCT images of 20 patients taken before and after treatment were included in the study. The following radiographic parameters were measured: buccal/palatal bone plate thickness measured in three locations, 0.5 mm, 3.5 mm, and 5 mm from the margin of alveolar process; cemento-enamel junction-crest distance (CEJ-C) measured at buccal (CEJ-B) and palatal/lingual (CEJ-P) aspects. RESULTS: After treatment there were insignificant changes in CEJ-C and thickness of buccal/palatal plates for all the dental groups except for incisors and premolars. CEJ-B increased by 1.43 mm on premolars and CEJ-P by 1.65 mm on incisors and by 0.31 mm on premolars. On the incisors, the buccal plate width increased significantly, by 0.2 mm and 0.44 mm at 3.5-mm and 5-mm measurement points. On premolars, the buccal plate width decreased in three measuring points by 0.27 mm, 0.37 mm, and 0.25 mm. CONCLUSIONS: Piezocision-assisted orthodontic maxillary arch expansion does not cause evident negative changes of cortical plates except for the premolar region. Therefore, premolars may be at greater risk of buccal plate loss than other teeth.

Dental tribology: a systems approach.

PURPOSE: This article presents the new system approach for the biotribological description of the stomatognathic system, with particular emphasis on one of its subsystems, the dental organ. METHODS: The peculiarity of the dental organ is emphasised, associated with a specific autonomic environment, next to the external environment, resulting from the impact of the organism on the dental organ. The autonomic environment increases the number of relations between elements in the dental organ and hinders its examination. RESULTS: The characteristics of the dental organ are described. Its main elements, their properties, and the relationships between them are identified, and the system's functions, inputs and outputs are presented. The systems approach addresses these difficulties, enabling the analysis of the dental organ and its tribological characteristics. CONCLUSIONS: The dental organ has an "autonomic" environment, which significantly increases the number of tribological relationships and complicates their analysis. Knowledge of the tribological attributes of the dental organ can be useful in studying detailed aspects of the function of the dental organ. The specific features of the analysed system and the uniqueness of its structure necessitate the use of appropriate methodology for testing the tribological properties.

Effect of the material's stiffness on stress-shielding in osseointegrated implants for bone-anchored prostheses: a numerical analysis and initial benchmark data.

PURPOSE: This study attempted to establish the link between design of implants for bone-anchored prostheses and stress-shielding, affecting the stability of the bone-implant coupling using numerical approach. The objectives were to share a numerical model capable to evaluate the long-term stability of implants and to use this model to extract data sets showing how shape and material stiffness of threaded, press-fit and modular press-fit implants affect stress-shielding intensity. METHODS: Three designs were considered: threaded, press-fit and modular press-fit. The effect of shape and material stiffness of each design on stress-shielding intensity was assessed using Young's modulus (10 to 210 GPa). Furthermore, the impact of the diameter of percutaneous part (10 to 18 mm) and thickness of medullar part (5 to 1 mm) was investigated for the modular press-fit implant. RESULTS: The threaded design generated 4% more bone mass loss at the distal femur but an overall loss of bone mass was by 5% lower to press-fit design. The influence of Young's modulus on bone mass changes was noticeable for modular press-fit implant, depending on diameter of percutaneous or medullary part. A 20 GPa change of stiffness caused a bone mass change from 0.65% up to 2.45% and from 0.07% up to 0.32% for percutaneous parts with 18 mm and 10 mm diameter, respectively. CONCLUSIONS: Results suggested that threaded implant provides greater stability despite an increased bone loss at the distal femur. Altogether, this work provided an initial model that could be applied in subsequent studies on the long-term stability of current and upcoming implants.

The Influence of Geometry of Implants for Direct Skeletal Attachment of Limb Prosthesis on Rehabilitation Program and Stress-Shielding Intensity.

The purpose of the research was to evaluate the influence of selected parameters of the implants for bone anchored prostheses on possibility of conducting static load bearing exercises and stress-shielding intensity. A press-fit implant, a threaded implant, and the proposed design were compared using the finite element method. For the analyses two features were examined: diameter (19.0 - 21.0 mm) and length (75.0 - 130.0 mm). To define the possibility of conducting rehabilitation exercises the micromotion of implants while axial loading with a force up to 1000 N was examined to evaluate the changes at implant-bone interface. The stress-shielding intensity was estimated by bone mass loss over 60 months. The results suggest that, in terms of micromotion generated during rehabilitation exercises, the threaded (max. micromotion of 16.00 µm) and the proposed (max. micromotion of 45.43 µm) implants ensure low and appropriate micromotion. In the case of the press-fit solution the load values should be selected with care, as there is a risk of losing primary stabilisation. The allowed forces (that do not stimulate the organism to generate fibrous tissue) were approx. 140 N in the case of the length of 75 mm, increasing up to 560 N, while using the length of 130 mm. Moreover, obtained stress-shielding intensities suggest that the proposed implant should provide appropriate secondary stability, similar to the threaded solution, due to the low bone mass loss during long-term use (improving at the same time more bone remodelling in distal Gruen zones, by providing lower bone mass loss by approx. 13% to 20% in dependency of the length and diameter used). On this basis it can be concluded that the proposed design can be an appropriate alternative to commercially used implants.

Influence of dental materials on hardness and Young's modulus of the surface layers of tooth enamel formed as a result of friction.

PURPOSE: The purpose of this work was to determine the influence of dental materials used as permanent fillings on the mechanical properties of the tooth enamel surface layer subjected to friction with these materials. METHODS: Dental composite materials (five types) were differentiated in terms of size and shape of the filler particles and matrix type over the course of tests on the chewing simulator under two different loads set during friction. Next, it was measured values of wear and nanoindentation for the resulting friction rates on the enamel (3 different load ranges). RESULTS: It was found that the enamel's resistance to tribological wear is significantly higher than that of the tested dental materials. It is also important to note that, depending on the penetration depth of the indenter (depends on the indenter pressure), different hardness values and Young's modulus of enamel were obtained after friction with different dental materials. This demonstrates the formation of a surface layer with different properties than the native material. CONCLUSIONS: Analysis of the obtained results suggests the existence of different tribological wear mechanisms, as evidenced by significant differences in the wear values of dental materials and enamel. The data show that the enamel surface layer modified by the contacting dental material is shaped to a certain depth, and different thickness ranges of the changed layer have different properties.

A Comparative Analysis of Standardised Threads for Use in Implants for Direct Skeletal Attachment of Limb Prosthesis: A Finite Element Analysis.

The aim of the research was to determine the optimal thread's shape to be used in implants for direct skeletal attachment of limb prosthesis. In addition, by testing appropriate parameters' modification of the suitable thread, an attempt was made to maximise its effectiveness. The analyses included three thread types described in the ISO standards: shallow, symmetrical, and asymmetrical. The obtained results suggest that shallow thread ensures the lowest equivalent and directional stress peaks generated in the bone as well as favourable stress patterns and profiles during implant loading in relation to symmetrical and asymmetrical threads. Moreover, shallow thread ensured the generation of single equivalent and directional stress peaks, while symmetrical and asymmetrical threads provided additional stress peak for equivalent as well as for each of directional peaks. Subsequently, optimisation of the shallow thread's shape was conducted by changing two relevant thread's parameters (flank angle and rounding arc) which influence the generated stress distribution. The highest reduction of stress peaks was obtained while reducing the rounding arc by 0.2 mm. Therefore, it can be stated that the proposed modification of the HA thread can lead to obtaining a higher biomechanical effectiveness of implants for direct skeletal attachment of limb prosthesis.

Assessment of the effect of the corticotomy-assisted orthodontic treatment on the maxillary periodontal tissue in patients with malocclusions with transverse maxillary deficiency: a case series.

BACKGROUND: The aim of the study was to assess the effect of corticotomy-assisted orthodontic treatment on soft tissue clinical parameters in patients with malocclusions with transverse maxillary deficiency. METHODS: The study included 20 generally healthy adult individuals with malocclusion, who underwent a corticotomy-assisted orthodontic treatment in maxilla. During the corticotomy performed after full-thickness flap elevation, only the buccal cortical plate was cut with the use of OTS-7, OTS7-4, OTS7-3 ultrasound tips of the piezosurgery device (Mectron s. p. a., Italy). A clinical examination was performed prior to the corticotomy procedure, then repeated - 3, 6, 9 and 12 months after the procedure. The following parameters were assessed: FMPI (full mouth plaque index), FMBOP (full mouth bleading on probing), PD (probing depth), CAL (clinical attachment level), GR (gingival recession height), RW (recession width), PH (papilla height), PW (papilla width), BS (bone sounding), biotype and KT. RESULTS: There was a statistically significant reduction in PD (mean difference: 0.06; 95% Cl: - 0.33, - 0.18), CAL (mean difference: 0.07; 95% Cl: - 0.33, - 0.19), PH (mean difference: 0.26; 95% Cl: - 0.47, 0.05) and BS (mean difference: 0.13; 95% Cl: - 0.41, - 0.14) after the treatment. Statistically significant changes were also noted in relation to KT (mean difference: 0.17; 95% Cl: - 0.07, 0.27) and biotype (mean difference: 0.07; 95% Cl: 0.26, 0.39), which thickness increased significantly after the treatment. No statistically significant differences were observed in GR, RW and PW. CONCLUSIONS: The corticotomy-assisted orthodontic treatment did not jeopardize the periodontal clinical status in maxilla. There is a need for further studies on a larger number of patient to compare the clinical findings with a control group as well as in patients with conventional orthodontic treatment in a longer follow-up time to find out more about the post-treatment periodontal tissue changes and stability.

A comparative analysis of internal bone remodelling concepts in a novel implant for direct skeletal attachment of limb prosthesis evaluation: A finite element analysis.

Nowadays, numerous internal bone remodelling concepts are under development, in order to estimate long-term functionality of implants by evaluating the intensity of stress-shielding effect. This effect is also analysed for the implants for direct skeletal attachment, considered as a better exoprosthesis fixation method than prosthetic sockets. Most of bone remodelling approaches are based on basic concepts, differing with certain assumptions, which may affect the accuracy of the results. This article compares commonly used internal bone remodelling concepts and evaluates the functionality of the proposed Limb Prosthesis Osseointegrated Fixation System for direct skeletal attachment of limb prosthesis in comparison with two currently available implants: the Intraosseous Transcutaneous Amputation Prosthesis and the Osseointegrated Prostheses for the Rehabilitation of Amputees. Three concepts were chosen: without and with lazy zone and with the use of quadratic formula which considers bone overloading. Therefore, three finite element models were created with identical femur implanted with each of analysed implants. The implants were loaded with loads that refer to two stages of gait cycle (heel strike and toe-off). The analysed concepts have given similar results, allowing to assume that each of them can be successfully used to estimate internal bone remodelling around analysed implants for direct skeletal attachment of limb prosthesis. The results also present higher functionality of the proposed implant for direct skeletal attachment of limb prosthesis due to a significant reduction in stress-shielding in the analysed areas around implant in comparison with the Intraosseous Transcutaneous Amputation Prosthesis and the Osseointegrated Prostheses for the Rehabilitation of Amputees. It suggests that the proposed design is a better alternative to the currently used solutions.

Biomechanical evaluation of a novel Limb Prosthesis Osseointegrated Fixation System designed to combine the advantages of interference-fit and threaded solutions.

PURPOSE: The study was aimed at biomechanical evaluation of a novel Limb Prosthesis Osseointegrated Fixation System (LPOFS) designed to combine the advantages of interference-fit and threaded solutions. METHODS: Three cases, the LPOFS (designed), the OPRA (threaded) and the ITAP (interference-fit) implants were studied. Von-Mises stresses in bone patterns and maximal values generated while axial loading on an implant placed in bone and the force reaction values in contact elements while extracting an implant were analysed. Primary and fully osteointegrated connections were considered. RESULTS: The results obtained for primary connection indicate more effective anchoring of the OPRA, however the LPOFS provides more appropriate stress distribution (lower stress-shielding, no overloading) in bone. In the case of fully osteointegrated connection the LPOFSs kept the most favourable stress distribution in cortical bone which is the most important long-term feature of the implant usage and bone remodelling. Moreover, in fully bound connection its anchoring elements resist extracting attempts more than the ITAP and the OPRA. CONCLUSIONS: The results obtained allow us to conclude that in the case of features under study the LPOFS is a more functional solution to direct skeletal attachment of limb prosthesis than the referential implants during short and long-term use.

Tribological characteristics of enamel-dental material contacts investigated in vitro.

PURPOSE: The aim of this study was to investigate wear and friction behaviour of tooth enamel against selected dental restorative materials. METHODS: The experimental material was obtained under simulated mastication, during which human tooth enamel was sub- jected to friction and wear in contact with composite dental materials: Estelite Sigma and FulFil Extra. RESULTS: The results have shown that the enamel's resistance to tribological wear is significantly higher than the resistance of the dental materials tested. The microscopic observations of the sample surfaces subsequent to the tribological research as well as the analysis of the chemical composition of the surface layer confirm the existence of diverse tribological wear mechanisms dependent on the type of dental materials used. CONCLUSIONS: Composite materials such as Estellite Sigma and FulFil Extra are characterized by greater resistance to wear and are less destructive to enamel than the material investigated by the authors earlier. It has also been stated that the spherical shape of the filler particles (Estellite Sigma) has a beneficial effect in reducing enamel wear.

Retention force assessment in conical crowns in different material combinations.

The puprose of this study was to evaluate retention force of conical double crowns in two material connections: gold casting alloy/gold casting alloy and gold casting alloy/gold electroforming alloy. 12 crown pairs of both material connections with the cone angles of 2°, 4° and 6° were made. Experiment of 10.000 in-and-out cycles was performed using a new device which allows the retentive force to be measured in continuous way without necessity of moving the samples to another device. It has been found that the higher the retentive force values, the lower the cone angle. Dispersion of the retention value was similar in both groups, but when cone angle was 2° or 4°, stability of retention force with the passage of time was higher in combinations with electroformed copings. The optimum solution was the cast alloy/cast alloy connection but only with cone angle 6°. However, retentive values seem to be too low to achieve proper retention of dentures.

Long-term follow-up of conical crown-retained dentures fabricated using different technologies.

This study presents the results of a long-term clinical evaluation of conical crown-retained dentures fabricated using different technologies. Four different material connections between the outer and inner crowns were used: cast gold/cast gold, cast gold/electroforming, nonprecious alloy/electroforming, and titanium abutment/electroforming. Technical failures and retention values were assessed. The best clinical outcome was found with dentures in which both crowns were cast from gold alloy. The most frequent technical failures were observed in restorations with electroformed outer crowns. Better clinical outcomes were noted when the electroformed outer crowns were used in dentures retained by implants as compared to dentures on natural dentition.