Denis Vojvodić

Differences in articular-eminence inclination between medieval and contemporary human populations

The articular-eminence inclination is an important element in the biomechanics of the temporomandibular joint and the entire masticatory system; however, very little is known about this inclination in archaeological human populations. Therefore, the aim of this study was to determine the values of, in addition to the differences between, the articular-eminence inclination in medieval and contemporary human populations. The study was carried out on two dry skull groups. The first group consisted of 14 dry skulls from the medieval culture group Bijelo Brdo (BB) of East Croatia, and the other consisted of 137 recent dry skulls from the osteologic collection of the Institute of Anatomy (IA) in Zagreb. All BB skulls were dentulous, whereas the IA skulls were divided into dentulous and edentulous groups. The articular-eminence inclination was measured in relation to the Frankfurt horizontal plane on digital images of the skulls two lateral views using AutoCAD computer software. The mean value of the articular-eminence inclination in the BB sample group (49.57°) was lower, with a statistical significance (p<0.01), than those of the IA dentulous (61.56°), the IA edentulous (62.54°), and all the combined IA (61.99°) specimens. Because the values of the articular-eminence inclination can vary a lot with reference to the number of specimens and the different methods used for measuring, the obtained values yield only orientational information. Further investigations including a larger number of medieval specimens are needed to confirm the results obtained from this study.

Oral Health-Related Quality of Life in Different Types of Mandibular Implant Overdentures in Function Longer Than 3 Years.

PURPOSE The aim of this study was to evaluate the oral health-related quality of life (OHRQoL) of patients treated with three different types of mandibular implant overdentures (IOD) after at least 3 years in function. MATERIALS AND METHODS A total of 122 patients treated with mini implant (50), locator (56), or bar (16) mandibular IODs participated. Modified plaque (PI) and gingival (GI) indices were also assessed. RESULTS Older patients and patients with mini mandibular IODs were the most satisfied with their OHRQoL. The bar overdenture presented the worst PI and GI results. CONCLUSION The mini mandibular overdenture patients were assessed with a better OHRQoL than those with bar and locator IODs.

Occlusal plane orientation in Klinefelter syndrome (47, XXY males)

Occlusal plane position was analysed cephalometrically in 35 Klinefelter adults (47,XXY) and compared with 60 eugnath control males (46,XY). The significantly smaller angles between the occlusal plane and the cranial base (NSL-OLs) and between the occlusal plane and the Frankfort horizontal plane (Fr-OLs) were obtained in 47,XXY males (P < 0.01), while the angles between the maxillary base and the occlusal plane (NL-OLs) and between the Campers line and the occlusal plane (Camp.-OLs) were not significantly different (P > 0.05) from the control group. Significantly smaller angles between the occlusal plane and the cranial base (NSL-OLs) and between the occlusal plane and the Frankfort horizontal plane (Fr-OLs) in Klinefelter males are attributed to the hereditary influence of an extra X chromosome on the smaller growth of the cranial base and the greater growth of the lower border of the mandible. Although the maxilla was also shifted forward in XXY males in relation to the cranial base it was not enough to compensate for the hereditary influence, due to the greater growth of the lower border of the mandible and the smaller cranial base in 47, XXY males, on the inclination of the occlusal plane to the Frankfort horizontal plane and the cranial base. The forward shift of the maxilla was sufficient to compensate for the inclination of the occlusal plane in 47, XXY males to the maxillary base and the Campers line (P > 0.05).

A two-step (altered cast) impression technique in the prosthetic rehabilitation of a patient after a maxillectomy: a clinical report.

This clinical report describes the prosthetic rehabilitation complicated by trismus (as a consequence of surgery and radiation therapy) of a patient with an acquired maxillary defect, after surgical removal of the right maxillary sinus tumor. The patient was restored with a partial removable dental prosthesis with a hollow bulb obturator to obtain orofacial rehabilitation and defect obturation. Precise obturation requires an accurate impression of the resection defect. A 2-step impression was performed because of trismus. A primary maxillary impression was made with an irreversible hydrocolloid, while a secondary (altered cast) impression was made with a silicone material by using the obturator cast framework as a tray. In that way an altered cast was produced. Subsequently, an obturator prosthesis was processed with a conventional technique.

Surface structural changes of feldspathic ceramics before and after immersion in corrosive medium using Atomic Force Microscopy

Abstract Ceramics are attractive dental materials as a result of their supe- rior aesthetics and biocompatibility. However, they are brittle and prone to premature failure, especially at repeated contact strain and in moist environments. The chemical stability of dental ceramics is important, because it directly affects mechanical properties and aesthetic value of restorations. The aim of this study was to investigate the effects of a corrosive agent, i.e. 4% acetic acid, on the surface of glazed and unglazed feldspathic ceramics. Metal-ceramic plates (9.0 × 9.0 × 1.2 mm) composed of a Ni-Cr alloy (Wiron 99, Bego Germany) and glazed or unglazed feldspathic ceramics (IPS Classic, Ivoclar-Vivadent, Schaan, Liechtenstein) were prepared according to the manufacturer‧s instructions. The samples were immersed in the solution at 80 °C and kept there for 16 h (ISO 6872). The surfaces of the samples before and after immersion in the corrosive medium were examined by atomic force microscopy (AFM). The pre- and post- corrosion AFM images of the surfaces of the feldspathic ceramics samples clearly show that the glazed surfaces are much less prone to deterioration by corrosion than the unglazed ones.

Differences in skeletal components of temporomandibular joint of an early medieval and contemporary Croatian population obtained by different methods

The temporomandibular joint (TMJ) is one of the most complex joints in the human body. The anatomical configuration of the TMJ allows for a large range of mandibular movements as well as transmission of masticatory forces and loads to the skull base. The measurements of the TMJs anatomical structures and their interpretations contribute to the understanding of how pathological changes, tooth loss, and the type of diet (changing throughout human history) can affect biomechanical conditions of the masticatory system and the TMJ. The human TMJ and its constituent parts are still the subject of extensive investigation and comparisons of measurement methods are being made in order to determine the most precise and suitable measurement methods. The aim of this study has been to examine the morphology of skeletal components of TMJ of an early medieval population (EMP) in Croatia and to compare measured values with TMJ values of the contemporary Croatian population (CP) using various methods of measurement. The study was performed on 30 EMP specimens - human dry skulls, aged from 18 to 55 years, and 30 CP human dry skulls, aged from 18 to 65 years. Only fully preserved specimens (in measured areas) were included. The articular eminence (AE) inclination was measured in relation to the Frankfurt horizontal using two methods. Also, the AE height (glenoid fossa depth) and the length of the curved line - highest to the lowest point of the AE were measured. Measurements were performed on lateral skull photographs, panoramic radiographs and lateral cephalograms using VistaMetrix software on skull images. The results were statistically analyzed using SPSS statistical software. No statistically significant differences were obtained for AE parameters between the EMP and CP populations independent of age and gender. However, statistically significant (p<0.05) differences were revealed when comparing results of three different measuring methods. It could not be determined which of the used measurement methods is the most accurate due to the different results obtained as well as the presence of possible shortcomings and limitations of the various methods (measuring points are difficult to determine and/or they are not clearly observed in the investigated images to be precisely marked and measured; distortion and magnification of structures on radiographic images are present). Therefore, due to the limitations of this study, the obtained results could serve only as orienting information.

Articular eminence inclination in medieval and contemporary Croatian population

Articular eminence inclination (AEI) of the temporomandibular joint leads the mandible in its movements. Therefore, the aim of the present study was to determine AEI values in medieval (MP) and recent (RP) Croatian population. The study was carried out on two groups of specimens: first group with 30 MP human dry skulls, while the other, serving as control group consisted of 137 dry skulls. The AEI was measured on lateral digital skull images as the angle between the best fi t line drawn along the posterior wall of the articular eminence and the Frankfurt horizontal plane. No statistically significant (p>0.05) differences between the left and right side AEI were found between MP skulls and RP skulls. The mean value of MP AEI was 45.5˚, with a range of 20.9˚-64˚. The mean RP AEI value was steeper (61.99˚), with a range of 30˚-94˚. Difference between the mean MP and RP AEI values was statistically significant (p<0.05). Values of AEI vary a lot. Nonsignificant differences between the left and right side AEI confirmed the natural left-right side asymmetry. The values of AEI differ between the RP and MP groups, most probably due to different type of food consumption in medieval time, and consequently different masticatory loads and forces.