Amir Ćatić

Qualitative evaluation of elderly home residents' fixed and removable prostheses in relation to the ADL index

UNLABELLED Functional diversity and biopsychosocial state is a significant issue, which greatly influences elderly oral health and state of fixed and removable prostheses. OBJECTIVES The goal of the investigation was to evaluate the quality of fixed and removable prostheses in a group of elderly home residents in relation to the ADL index. METHODS The group consisted of 175 institutionalised elderly, mean age 76.8 years. Special care need was assessed on ADL scale. To evaluate the quality and need for replacement of fixed and removable prostheses Karlssons and modified Nevalainen et al. indices were used. RESULTS Spearmans correlation analysis showed significant correlation of ADL index scores and both Karlssons index values (rho=-0.468, p<0.01) as well as for modified Nevalainens indices (rho=-0.572, p<0.01). Lower ADL score was correlated with poorer oral hygiene and condition of fixed or removable dentures. It was determined that 87% of the examined patients were in objective need of fixed, removable or combined prosthodontic treatment. CONCLUSIONS The study showed that lower ADL index scores of functionally dependent elderly patients correlate with poorer condition of fixed and removable prostheses and greater need of fixed, removable or combined prosthodontic treatment.

Psychological Status and Recurrent Aphthous Ulceration

Aim of this study was to explore and compare association of PD (psychological distress) and cardiovascular risk behaviors, conditions and diseases in Croatian adult population. The sample of this study consisted of 3,229 respondents. Psychological distress status was measured by the five-item Mental Health Scale (MHI-5) of the Short Form questionnaire (SF-36), hence one distinguished subgroup consisted of population with PD and other without PD. Prevalence of cardiovascular risk behaviors, cardiovascular risk conditions and self-reported cardiovascular diseases within each subgroup were calculated. During the follow up period physical inactivity remained the only risk behavior showing significant difference between PD status subgroups for both genders demonstrating higher prevalence in men and women with PD. During follow up period hypertension, myocardial infarction, angina pectoris and self-reported heart failure in women remained constant in showing statistically significant prevalence difference among population with and without PD. In men that type of constant association was shown only for heart failure.

Measurements of the sagittal condylar inclination: intraindividual variations

Abstract Aims: Sagittal condylar inclination is an important parameter during fabrication of prosthetic restorations. Existing data about intraindividual variations of sagittal condylar inclination are scarce. The purpose of this study was to investigate intra- and interindividual variations of the sagittal condylar inclination, depending on the position of the condyle in the temporomandibular joint. Methodology: The study included 51 subjects with Angle’s Class I occlusion (21–32 years of age, mean 25·1). Measurements were done using an electronic axiograph. After a paraocclusal tray was fixed in the mouth, every subject had to make three protrusive movements, from which the device’s software calculated the mean left and mean right sagittal condylar path. The mean left and right condylar path of each subject was divided into three equal sequences, based on whole condylar path length. Condylar inclination values for the first, second and third movement sequences were calculated. Results: Results showed significant differences between movement sequences (P<0·05). For the left joint, condylar inclination values in the first condylar movement sequence demonstrated, on the average, 14·4% higher values compared to the second movement sequence, and 39·2% higher values than in the third movement sequence. For the right joint, the first condylar movement sequence demonstrated, on the average, 15·8% higher values compared to the second movement sequence, and 41·5% higher values than the third movement sequence. Conclusions: Results suggest that condylar movement in the sagittal direction is not uniform. Mean left and mean right condylar inclination values do not necessarily describe the actual condylar path, nor do they give adequate information for articulator setup. Left–right side condylar inclination differences greater than 10° can be considered as normal.

CP Ti Fabricated by Low Temperature Extrusion of HDH Powder: Application in Dentistry

Powder metallurgy (PM) commercial purity titanium (CP Ti) was fabricated and studied, with an aim of utilization for dental application. PM CP Ti was manufactured using a cost effective approach, where affordable hydrogenation–dehydrogenation (HDH) process Ti 99.4 wt.% powder was consolidated via the following sequence of PM techniques: cold isostatic pressing, warm vacuum pressing at 420 °C and warm direct extrusion at 500 °C. The paper presents the first studies on processing, microstructure, testing of mechanical properties, fatigue performance and bonding strength with different veneer coatings. By employed consolidation process sound material with low porosity (1.5%) and sustained oxygen content (0.21 wt.%) was attained. The tensile properties obtained for PM CP Ti (UTS = 701 MPa, YS0.2 = 512 MPa, ε = 13 %) were improved over to those for cast / milled CP Ti Grade 4 reference, the material commonly used in dentistry. Tested using the ISO 14801 standard for dental implants, the samples machined from PM CP Ti showed fatigue performance similar to CP Ti Grade 4. PM CP Ti used as a metal base material in restoration metal – ceramic systems showed very good bond strength with three commercially available veneering ceramics and complied with the ISO 9693 standard. Within the limitations of this paper, the preliminary results demonstrated that performance of economic PM CP Ti is equal or superior to CP Ti Grade 4 reference material and it can be used in prosthodontics.

Bioactive Ti + Mg composites fabricated by powder metallurgy: The relation between the microstructure and mechanical properties

Metallic implant materials are biomaterials that have experienced major development over the last fifty years, yet some demands posed to them have not been addressed. For the osseointegration process and the outcome of endosseous implantation, it is crucial to reduce the stress shielding effect and achieve sufficient biocompatibility. Powder metallurgy (PM) was utilized in this study to fabricate a new type of titanium (Ti) + magnesium (Mg) bioactive composite to enable stress-shielding reduction and obtain better biocompatibility compared with that of the traditional Ti and Ti alloys used for dental implants. Such composites are produced by well-known cost-effective and widely used PM methods, which eliminate the need for complex and costly Ti casting used in traditional implant production. The relation between the microstructure and mechanical properties of as-extruded Ti + (0-24) vol% Mg composites was investigated with respect to the Mg content. The microstructure of the composites consisted of a biodegradable Mg component in the form of filaments, elongated along the direction of extrusion, which were embedded within a permanent, bioinert Ti matrix. As the Mg content was increased, the discrete filaments became interconnected with each other and formed a continuous Mg network. Youngs modulus (E) of the composites was reduced to 81 GPa, while other tensile mechanical properties were maintained at the values required for a dental implant material. The corrosion behavior of the Ti + Mg composites was studied during immersion in a Hanks balanced salt solution (HBSS) for up to 21 days. The elution of Mg pores formed at former Mg sites led to a further decrease of E to 74 GPa. The studied compositions showed that a new Ti + Mg metallic composite should be promising for load-bearing applications in endosseous dental implants in the future.

Reproducibility of the obtained centric relation records in patients with disc displacement with reduction

Objective The aim of this study was to investigate reproducibility of the position of centric relation in patients with disc displacement with reduction. Materials and methods The test group included 30 subjects, diagnosed with disc displacement with reduction in right, left or both joints. The control group included 12 individuals with no signs and symptoms of temporomandibular disorders. Using chin point guidance with a jig, centric relation record was made three times by every participant, in a single session. Left and right condylar position for each centric relation record was determined and recorded using the electronic ultrasonic measuring device. The data were transferred to the computer, processed and analyzed. Condylar distances between centric relation records were measured (anteroposterior, vertical, transversal and linear values), and the data were statistically analyzed using the t and the F tests. Results No statically significant difference was found between the test and the control groups. Two thirds of study participants demonstrated condylar position of the repeated centric relation recording within the area of 0.3 mm in diameter. For more than 90% of participants that area was within 0.4 mm. Conclusions There is no difference in reproducibility of the centric relation between patients with disc displacement with reduction and healthy temporomandibular joint individuals (p>0.05). When doing centric relation record on a patient with disc displacement with reduction there is no need for previous splint therapy and standard precautions are acceptable. The obtained results must be interpreted within the experimental group, and not projected on the other groups of temporomandibular disorders.

Titanium-Magnesium Composite for Dental Implants (BIACOM)

We report on the study on the titanium-magnesium (Ti–Mg) bioactive metal-metal composite utilized for a fabrication of dental implants. The biomedical Ti-12vol.%Mg composite, named BIACOM, is manufactured using a cost effective approach, where a mixture of elemental Ti and Mg powders is extruded at low temperature to sound profiles. Microstructure of composite comprises filaments of biodegradable Mg component, which are arrayed along extrusion direction and are homogenously distributed within permanent, bioinert Ti matrix. Compared to Ti Grade 4, the reference material used for dental implants, the properties of as-extruded composite include significantly reduced Young’s elastic modulus (92.1 GPa) and low density (4.12 g.cm−3), while the mechanical strength of Ti Grade 4 is maintained. Dynamic testing of dental implants fabricated from as-extruded composite, realized to follow the ISO 14801 standard for endosseous dental implants, confirms fatigue performance of BIACOM implants equal to the one of the reference material. Exposure of as-extruded composite samples to Hank’s solution, realized in order to simulate behavior in human body over the time after implantation, yields gradual dilution of Mg from composites surface and volume. Corroded Mg leaves at prior Mg filament sites pores within Ti matrix, which remains intact. This provides further decrease of Young’s modulus and enhances macro and micro roughness at implants surface. As a result, BIACOM shows improved mechanical compatibility (i.e., reduction of stress-shielding) and better osseointegration potential.

Centric slide in different Angle's classes of occlusion

The purpose of this study was to test the possible differences in centric slide values between different Angles classes of occlusion. The study included 98 participants divided into four groups: Angles class I, Angles class II, subdivision 1, Angles class II, subdivision 2 and Angles class III. All recordings were obtained using an ultrasound jaw tracking device with six degrees of freedom. The distance between the maximum intercuspation (reference position) and the centric occlusion was recorded at the condylar level. Anteroposterior, superoinferior and transversal distance of the centric slide were calculated for each participant, and the data were statistically analyzed (analysis of variance and Newman-Keuls post hoc test). No statistically significant difference was found in the anteroposterior and transversal distance of the centric slide between tested groups, while Angles class II, subdivision 2 showed smaller vertical amount of the centric slide compared to Angles class I and class II, subdivision 1. None of the 98 participants showed coincidence of centric occlusion and maximum intercuspation. Our results suggest that coincidence of the maximum intercuspation with the centric occlusion should not be expected. Smaller extent of the vertical distance of the centric slide could be morphological and a functional expression characteristic of the Angles class II, subdivision 2.

Titanium Ions Release from an Innovative Titanium-Magnesium Composite: an in Vitro Study.

BACKGROUND The innovative titanium-magnesium composite (Ti-Mg) was produced by powder metallurgy (P/M) method and is characterized in terms of corrosion behavior. MATERIAL AND METHODS Two groups of experimental material, 1 mass% (Ti-1Mg) and 2 mass% (Ti-2Mg) of magnesium in titanium matrix, were tested and compared to commercially pure titanium (CP Ti). Immersion test and chemical analysis of four solutions: artificial saliva; artificial saliva pH 4; artificial saliva with fluoride and Hank balanced salt solution were performed after 42 days of immersion, using inductively coupled plasma mass spectrometry (ICP-MS) to detect the amount of released titanium ions (Ti). SEM and EDS analysis were used for surface characterization. RESULTS The difference between the results from different test solutions was assessed by ANOVA and Newman-Keuls test at p<0.05. The influence of predictor variables was found by multiple regression analysis. The results of the present study revealed a low corrosion rate of titanium from the experimental Ti-Mg group. Up to 46 and 23 times lower dissolution of Ti from Ti-1Mg and Ti-2Mg, respectively was observed compared to the control group. Among the tested solutions, artificial saliva with fluorides exhibited the highest corrosion effect on all specimens tested. SEM micrographs showed preserved dual phase surface structure and EDS analysis suggested a favorable surface bioactivity. CONCLUSION In conclusion, Ti-Mg produced by P/M as a material with better corrosion properties when compared to CP Ti is suggested.