Clinical evaluation of immediately loaded short hybrid self-tapping implants inserted in the posterior maxilla

UVOD: Ugradnja zubnih implanata danas predstavlja rutinsku terapiju parcijalne i totalne bezubosti, sa predvidljivim ishodom. Period razvoja oralne implantologije obeležio je konstantan rad na unapređenju makro- i mikro-dizajna implanta, materijala za implantaciju, kao i protokola opterećenja. Sa ciljem skraćenja sveukupnog vremena implantne terapije došlo je do predstavljanja protokola imedijatnog ili ranog opterećenja, koji su zamenili inicijalno preporučeni konvencionalni (tzv. dvofazni ili Branemarkov) protokol opterećenja, koji je podrazumevao period mirovanja od 3 do 6 meseci nakon ugradnje implanata. Analiza uspešnosti implantne terapije primenom implanata različitog makro- i mikro-dizajna, uz primenu protokola imedijatnog ili ranog opterećenja, sprovedena je u brojnim kliničkim studijama. Adekvatna primarna stabilnost implanta jedan je od osnovnih preduslova za uspeh implantne terapije, posebno kod primene protokola imedijatnog i ranog opterećenja, te su u pomenutim studijama implanti uglavnom ugrađivani u regije vilica sa dobrim kvalitetom kosti. Bočna regija gornje vilice, u kojoj preovlađuje slabiji kvalitet kosti, smatrana je nepovoljnom za primenu protokola imedijatnog ili ranog opterećenja, što je rezultiralo malim brojem studija na tu temu, kao i potrebom za dodatnom naučnom vrerifikacijom primene protokola imedijatnog opterećenja u pomenutoj anatomskog regiji. CILJ: Cilj ovog kliničkog istraživanja je bio da se ispita i uporedi uspešnost imedijatno i rano opterećenih kratkih, samourezujućih implanata ugrađenih u bočnu regiju gornje vilice, praćenjem i poređenjem odgovarajućih kliničkih parametara (vrednost primarne stabilnosti, promena vrednosti implantne stabilnosti u različitim vremenskim tačkama tokom perioda praćenja, vrednosti peri-implantne koštane resorpcije i vrednosti modifikovanog indeksa krvarenja (MBI) i modifikovanog plak indeksa (MPI)) i vrednosti kriterijuma uspešnosti. MATERIJAL I METOD: U ovu prospektivnu randomizovanu kliničku studiju, sa «splithmouth » dizajnom, bilo je uključeno osam pacijenata sa obostranom terminalnom bezubosti u gornjoj vilici...INTRODUCTION: The placement of endoseous dental implants to replace lost teeth has become a routine and predictable treatment modality. Dental implant macro- and microdesign, materials, as well as loading protocols have improved over time. The aim of shortening the overall treatment time has led to the introduction of immediate or early loading protocols that replaced the conventional (i.e. two-phase or Branemark`s) loading protocol, which required 3 to 6 months of undisturbed healing prior to implant loading. Several clinical trials have analysed immediate or early loading protocols using different implant designs. In most of these studies implants were inserted predominantly in sites with good bone quality in order to achieve adequate primary stability, which is one of the prerequisites for implant treatment success, but even more important when implants are loaded immediately. The posterior maxilla has been considered an anatomical region not suitable for immediate or early loading protocols, due to poor bone quality, and few studies on this could be found in the literature. AIM: The aim of the present study was to evaluate the overall success rate of immediately and early loaded short, hybrid self-tapping implants inserted in the posterior maxilla by analysing clinical parameters such as primary implant stability, implant stability changes during observation period, peri-implant crestal bone loss, peri-implant soft tissue healing and criteria for implant treatment success. MATERIAL AND METHOD: The present prospective, randomized controlled (splitmouth) clinical trial included eight patients with bilateral posterior edentulism in the maxilla. After meticulous planning and preoperative procedures done, each patient received 6 implants in total (split-mouth design) in the first and second premolar and first molar sites. Both sides of the maxilla were assigned randomly to either immediate (IL) or early (EL) loading group. Total of 48 implants were analyzed, 24 implants in both investigated groups..

Possibilities of reconstruction and implant-prosthetic rehabilitation following mandible resection

Introduction. Mandible reconstruction is still very challenging for surgeons. Mandible defects could be the consequence of ablative surgery for malignancies, huge jaw cysts, infection and trauma. Segmental resection of the mandible may compromise orofacial function and often lead to patients psychological disorders. Despite very frequent use of microvascular flaps, autogenous bone grafts are still very reliable technique for mandible reconstruction. Comprehensive therapy means not only mandible reconstruction, but prosthodontic rehabilitation supported by dental implants, which can significantly improve patients quality of life. The aim of this paper was to evaluate possible techniques of mandible reconstruction and to present a patient who had been submitted to mandible resection and reconstruction with autogenous iliac bone graft and prosthodontic rehabilitation with fixed denture anchoraged by disc-shaped implants in early loading protocol. Case report. Mandible reconstruction was performed simultaneously with resection. Autogenous iliac bone graft was taken, reshaped and placed in two parts, to the required optimal contour of the mandible. After graft consolidation, decision was made for prosthodontics rehabilitation with fixed dentures supported by implants. In addition to the standard preoperative procedures, planning was done based on a biomodel gained by rapid prototyping after CT scan. It offered a real 3D planning to obtain a proper shape, dimension and the position of implants. Conclusion. If bone dimensions of a reconstructed mandible are insufficient, like in the presented case, the use of basal osseointegrated implants may be a method of choice. Avoiding bone augmentation procedures, as well as early loading protocol for this type of implants, shorten the total rehabilitation time, which is very convenient for patients. Fixed denture supported by dental implants is the best solution for comprehensive rehabilitation after mandible resection. [Projekat Ministarstva nauke Republike Srbije, br. 175075

ANALASYS OF TWO LOW-COST AND ROBUST METHODS FOR INDOOR LOCALISATION OF MOBILE ROBOTS

This paper presents two simple and cost effective indoor localisation methods. The first method uses ceiling-mounted wide-view angle webcam, computer vision and coloured circular markers, placed on the top of a robot. Main drawbacks of this method are lens distortion and sensitivity to lighting conditions. After solving these problems, a high localisation accuracy of ±1cm is achieved at about 5 Hz sampling rate. The second method is a version of trilateration, based on ultrasound time of flight distance measurement. An ultrasonic beacon is placed on a robot while wall detectors are strategically placed to avoid an excessive occlusion. The ZigBee network is used for inter-device synchronisation and for broadcasting measured data. Robot location is determined as a solution to the minimisation of measurement errors. Using Nelder-Mead algorithm and low-cost distance measuring devices, a solid sub 5 cm localisation accuracy is achieved at 10Hz

Structural and electrical properties of geopolymer materials based on different precursors (kaolin, bentonite and diatomite)

Geopolymers (GP) were successfully synthesized from metabentonite (MB), metadiatomite (MD) and metakaolinite (MK). Characterization of their phase structure and microstructure was performed by XRD, FTIR, SEM/EDX methods. A SEM micrograph of GPMD shows a homogeneous surface with some longitudinal cavities in the gel, and it is significantly different from the micrographs of the other two geopolymer samples, GPMB and GPMK. A considerable amount of unreacted particles, as well as the presence of pores in the geopolymer matrix of GPMK and GPMD, indicate an incomplete reaction in the system. Aluminosilicate inorganic polymers, geopolymers, are quasi solid electrolytes which possess a high electrical conductivity at room temperature in relation to materials of similar chemical composi-tion. The highest conductivity was found for the sample obtained from GPMK, amounting to 2.14 x 10-2 Ω-1cm-1 at 700 oC. The corresponding activation energies of conductivity for this sample amounted to 0.33 eV in the temperature range of 500-700 oC. The geopolymer synthesized from metakaolin has good ionic conductivity values, which recommends it for use as an alternative material for an SOFC (Solid Ox-ide Fuel Cell)

The influence of alumino-silicate matrix composition on surface hydrophobic properties

The purpose of this investigation is to investigate the hydrophobicity of geopolymers, new alumino-silicate materials and the influence of Si/Al ratio on their surface properties. Contact angle measurement (CAM) as reliable indicator of hydrophobicity was determined for synthesized geopolymers using water and ethylene-glycol as reference liquids. Geopolymers were synthesized from various precursors: Kaolin, bentonite and diatomite. Characterization of phase structure and microstructure was performed by XRD, FTIR, SEM/EDX methods. Contact angle measurements confirmed that the geopolymers synthesized from metakaolin are the most porous, which can be explained by the smallest Si/Al ratio. The maximum value of contact angle and free surface energy (110.2 mJ/m2) has been achieved for geopolymer synthesized by diatoms (GPMD). SEM micrograph of GPMD shows a homogeneous surface with some longitudinal cavities in the gel and is significantly different from the micrographs of other two geopolymer samples, GPMB and GPMK

Stanje tvrdog i mekog periimplantnog tkiva u estetskoj regiji gornje vilice posle prezervacije alveolarnog grebena beta-trikalcijum fosfatom sa kolagenom tip I - studija sa jednogodišnjim periodom praćenja

Background/Aim. Alveolar ridge dimensional alterations following tooth extraction in the anterior maxilla often result in an inadequate bone volume for a correct implant placement. In order to obtain optimal bone volume various bone graft substitutes have become commercially available and widely used for socket grafting. The aim of this study was to examine and compare long-term clinical outcomes of dental implant therapy in the maxillary esthetic zone, after socket grafting with beta-tricalcium phosphate (TCP) combined with collagen type I, either with or without barrier membrane and flap surgery, after a 12-month follow-up. Methods. Twenty healthy patients were allocated to either C group (beta-TCP and type I collagen without mucoperiosteal flap coverage) or C+M group (beta-TCP and type I collagen barrier membrane with mucoperiosteal flap coverage). Following clinical parameters were assessed: implant stability (evaluated by a resonance frequency analysis - RFA), periimplant soft tissue stability (sulcus bleeding index - SBI, Mombelli sulcus bleeding index - MBI, periimplant sulcus depth, keratinized gingiva width, gingival level) and marginal bone level at the retroalveolar radiograms. Results. Within C+M group, RFA values significantly increased 12 weeks after implant installation compared to primary RFA values. Comparison between investigated groups showed a significantly reduced keratinized gingiva width in the C+M group compared to the C group after 3, 6, 9 and 12 months. Comparison between groups revealed significantly lower gingival level values in the C+M group at 9th and 12th month when compared to the C group. Conclusion. Implant treatment in the anterior maxilla could be effective when using a 9 months alveolar ridge preservation healing with combined treatment with beta-tricalcium phosphate and type I collagen, with regard to the peri-implant soft and hard tissue stability.Uvod/Cilj. Posle ekstrakcije zuba, dimenzionalne promene alveolarnog grebena u estetskoj regiji gornje vilice za posledicu često imaju nedovoljnu količinu kosti za ugradnju zubnih implanata. U vezi sa tim, primenjuju se različiti koštani zamenici sa ciljem očuvanja dimenzija alveolarnog grebena posle ekstrakcije zuba. Cilj rada bio je da se, posle prezervacije alveolarnog grebena beta-trikalcijum fosfatom (TCP) sa kolagenom tip 1, sa barijernom membranom i mukoperiostalnim režnjem i bez nje, ispitaju i uporede klinički ishodi zarastanja posle ugradnje zubnih implanata u estetskoj regiji gornje vilice, tokom jednogodišnjeg perioda praćenja. Metode. Dvadeset zdravih bolesnika podeljeno je u dve grupe: C (beta TCP/kolagen tip 1 bez barijerne membrane i mukoperiostalnog režnja) i C+M (beta TCP/kolagen tip 1 sa barijernom membranom i mukoperiostalnim režnjem). Praćeni su uobičajeni klinički parametri ishoda terapije: implantna stabilnost (analiza rezonantne frekvence), stanje mekih tkiva (indeks krvarenja, plak indeks, širina pripojne mukoze, recesija gingive) i nivo periimplantnog koštanog tkiva na retroalveolarnom radiogramu. Rezultati. U C+M grupi, implantna stabilnost posle 12 nedelja bila je značajno veća u odnosu na primarnu stabilnost. U C+M grupi, širina keratinizovane gingive bila je značajno manja posle 3, 6, 9 i 12 meseci u odnosu na C grupu. Recesija gingive bila je značajno veća u C+M grupi u odnosu na C grupu posle 9 i 12 meseci. Zaključak. Razmatrajući stabilnost mekog i tvrdog periimplantnog tkiva, terapija zubnim implantima može biti uspešna prilikom ugradnje u estetskoj regiji gornje vilice

A Multi-Year Study of Radioactivity in Surface Air and Its Relation to Climate Variables in Belgrade, Serbia

Activities of Be-7 and Pb-210 were monitored in surface air in Belgrade, Serbia, from 2004 to 2012. The measurements were taken from two locations, in an open field of a city suburb and in the central city area. The activities were determined on HPGe detectors by standard gamma spectrometry. The Be-7 activity shows a pronounced seasonal pattern, with the maximum in spring-summer and minimum in winter, while the Pb-210 activity exhibits two maxima, in autumn and late winter. The mean monthly concentrations measured at both sites are below 9 mBq/m(3) and 1.3 mBq/m(3) for Be-7 and Pb-210, respectively. The obtained correlation of the Be-7 activity with the number of sun-spots is not statistically significant. Relations of the radionuclides activities with climate variables (precipitation, temperature, relative humidity, cloud cover, sunshine hours, and atmospheric pressure) are also investigated, but the only significant correlations are found for the Be-7 activity with temperature and sunshine hours, and the Pb-210 activity with atmospheric pressure. The maximum Be-7 and Pb-210 activities corresponding to binned total monthly precipitation data imply different modes of the radionuclide scavenging from the atmosphere. During dry periods, accumulation of the radionuclides in the atmosphere leads to their increased activities, but no correlation was found between the activities and the number of consecutive dry days

Clinical significance of optimal red cell mass and plasma volume estimation methods

BACKGROUND: The aim of this study was to present and compare the results of proposed methods for optimal red cell mass and plasma volume (RCM&PV) estimation, and their influence on the interpretation of obtained results. MATERIAL AND METHODS: In 120/280 patients with polycythaemia rubra vera, subjected to RCM&PV determination with autologous erythrocytes in vitro labelled with 51Cr-sodium chromate, optimal volumes were determined using: 1. traditional ml/kg of: - the real body weight method (ml/kg RBW); - the optimal body weight method (ml/kg OBW). 2. the body weight, height, and sex based method (Retzlaff's tables), 3. the method recommended by the International Council for Standardization in Haematology (ICSH), based on body surface area. RESULTS: Different interpretation of the same results of 120 RCM&PV measurements was registered in 48/120 patients (40%). The greatest disagreement existed between ml/kg RBW and ml/kg OBW methods (in 39/120 subjects, 32.5%). In underweight patients the ml/kg RBW method, and in overweight patients the ml/kg OBW method, offered better agreement with ICSH&Retzlaff's methods. The ml/kg RBW method disagreed with ICSH&Retzlaff's methods and ml/kg OBW in 25% and 19.2% of patients respectively. ICSH and Retzlaff's methods disagreed in 10/120 patients (8.3%). The ICSH method yielded significantly lower optimal volumes than Retzlaff's. CONCLUSION: Three methods for optimal RCM&PV estimation lead to different interpretations of the same results of RCM&PV measurements with 51Cr-erythrocytes in 40% of patients. Two ml/kg body weight methods show greater disagreement in comparison with ICSH and Retzlaff's methods, which differ significantly. The ICSH method yields lower optimal values compared to Retzlaff's

Debromination of endo-(+)-3-Bromocamphor with Primary Amines

Reductive debromination of endo-(+)-3-bromocamphor with different primary amines followed by imine formation was investigated. This reaction requires simple experimental procedure without any organic solvent, metal or conventional reducing agent. A strong influence of amine polarity on the efficacy of debromination process was observed, and ethanolamine and ethylene diamine having sufficiently high boiling points can debrominate 3-bromocamphor giving corresponding camphanimines in good isolated yields. The mechanisms of debromination of 3-bromocamphor with ethanolamine and n-hexylamine were investigated at the B3LYP/6-311+G(d,p) level of theory. The radical mechanism was revealed, and it was shown that the reaction with more polar ethanolamine is energetically more favorable