Objectives: To compare the properties of calcium phosphate precipitation on four different bioactive surface preparations and one control surface in the simulated body fluid model with added collagen type I.
Material and Methods: Blasted titanium discs were treated with four different surface modifications, alkali and heat, sodium fluoride, anodic oxidation and hydroxyapatite coating. The discs were divided into five groups where one group, the blasted, served as control. The discs were immersed in simulated body fluid and collagen for 24 h, 3 days, 1 week and 2 weeks and then analysed by optical interferometry, scanning electron microscopy/energy dispersive X-ray analysis and X-ray photoelectron spectroscopy.
Results: All surfaces show small precipitates after 3 days which with longer immersion times increase. After 2 weeks the surfaces were completely covered with precipitates, and Ca/P ratios were approximately 1.3, independently on surface preparation. The fluoridated discs showed significantly (P ≤ 0.05) higher degree of CaP after one week of immersion as compared to the other surface preparations. The collagen type I content increased with time, as reflected by increased nitrogen content.
Conclusions: The results from this study indicate that a fluoridated titanium surface may favour precipitation of calcium phosphate in the presence of collagen type I, as compared to the other surface treatments of the present study.
Objectives: Cone-beam computed tomography in dentistry can be used in some countries by other dentists than specialists in radiology. The frequency of buying cone-beam computed tomography to examine patients is rapidly growing, thus knowledge of how to use it is very important. The aim was to compare the outcome of an investigation on the use of cone-beam computed tomography in Sweden with a previous Norwegian study, regarding specifically technical aspects.
Material and Methods: The questionnaire contained 45 questions, including 35 comparable questions to Norwegian clinics one year previous. Results were based on inter-comparison of the outcome from each of the two questionnaire studies.
Results: Responses rate was 71% in Sweden. There, most of cone-beam computed tomography (CBCT) examinations performed by dental nurses, while in Norway by specialists. More than two-thirds of the CBCT units had a scout image function, regularly used in both Sweden (79%) and Norway (75%). In Sweden 4% and in Norway 41% of the respondents did not wait for the report from the radiographic specialist before initiating treatment.
Conclusions: The bilateral comparison showed an overall similarity between the two countries. The survey gave explicit and important knowledge of the need for education and training of the whole team, since radiation dose to the patient could vary a lot for the same kind of radiographic examination. It is essential to establish quality assurance protocols with defined responsibilities in the team in order to maintain high diagnostic accuracy for all examinations when using cone-beam computed tomography for patient examinations.
Objectives: Temporomandibular disc is a mechanically robust fibrocartilage tissue exhibiting highly elastic compressive, shear, and tensile moduli with structurally dense extracellular matrix that supports functional loading of the joint. The aim of this study was to illustrate structural complexities of the superior and inferior disc surfaces, to demonstrate the robust mechanical ability of the disc as a whole may be due to depth-dependent regional/layered variation, and also to provide characterization data imperative for future tissue engineering efforts focused on restoring function to the joint.
Material and Methods: Nanoindentation was used to assess tissue zones in conjunction with detailed Transmission Electron Microscopy to define structural attributes that influence the temporomandibular disc function.
Results: The disc architecture adjacent to the superior surface was shown to have three distinct regional segments within the interface layer: 1-a surface peripheral layer; 2-subsurface region; and 3-a layer of helical matrix bundles. The inferior surface displayed an interface layer (20 µm) that showed limited cell populations with little depth-dependent structural variation, a stiffer elastic modulus and reduced energy dissipation compared to the superior surface. These data indicate that the primary function of the inferior surface is resistance to compression rather than load distribution during joint motion.
Conclusions: These are the first works that demonstrate that the superior central surface of the he temporomandibular disc is structured in depth-dependent isometric layers, each of which provides different mechanical function supporting the bulk tissue’s properties. From a clinical perspective these data have potential to define regions susceptible to fatigue that may translate to diagnostic criteria to better define the stages of dysfunction.
Objectives: A variety of diagnostic indices in orthodontics have been proposed to help in diagnosis and treatment planning. Pont’s Index was established to predict ideal maxillary dental arch width from the sum of mesiodistal widths of four upper incisors. The aim of this study was to assess the applicability of Pont’s Index to Lithuanian individuals.
Material and Methods: The sample comprised 52 subjects (age range from 18 to 35 years) with normal occlusion. Measurements were obtained directly from plaster casts using a digital calliper. Ideal arch widths were calculated for each subject according to Pont’s formulae, and the correlation coefficients were calculated between the measured and the calculated arch width values.
Results: Correlation between the measured width values and the corresponding values calculated according to Pont’s Index was moderate in all cases, with correlation coefficients values ranging from 0.59 (mandible) to 0.64 (maxilla) in first premolar’s area and 0.49 in both maxilla and mandible in first molar’s area (P < 0.05). Appropriate index values for Lithuanian individuals were assessed to be 85.57 in premolars and 66.24 in molars area.
Conclusions: According to the results of this study, there was no strong evidence to suggest that Pont’s Index could be reliably used to predict ideal arch width values in Lithuanian individuals.
Metastatic Tumours to the Oral Cavity: Report of Three Cases
Ioanna G. Kalaitsidou, Ioannis T. Astreidis, Konstantinos I. Kontos, Maria N. Lazaridou, Eleni T. Bourlidou, Domniki K. Gerasimidou, Natalia P. Vladika, Doxa L. Mangoudi
Background: Metastatic tumours to the oral cavity from distant organs are uncommon and represent approximately 1 - 3% of all oral malignancies. Such metastases can occur to the bone or to the oral soft tissues. Almost any malignancy from any site is capable of metastasis to the oral cavity and a wide variety of tumours have been reported to spread to the mouth.
Methods: Careful examination of the oral cavity and a high degree of clinical suspicion as well as a multidisciplinary approach are suggested.
Results: In this article we present three patients, a female and two males with metastatic tumours to the oral cavity, who were referred to our Department. The primary tumours were invasive lobular breast carcinoma, gastric adenocarcinoma and small cell lung carcinoma respectively.
Conclusions: Metastases to the oral cavity are quite uncommon among population. They usually present with symptoms similar to odontogenic infections and benign tumours, causing a delayed diagnosis and treatment.
