The Clinical Use of Fiber- Reinforced Composite

Uporaba vlaknima ojačanih kompozita dobila je na važnosti tek posljednjih nekoliko godina, premda se o njezinoj vrijednosti u stručnim stomatološkim radovima pisalo već u ranim šezdesetim godinama prošloga stoljeća. Vlaknima ojačani kompoziti mogu se razvrstati prema vrsti vlakana, njihovu smjeru, te prema obradi organskom smolom. Polietilenska, staklena, kevlar i ugljična vlakna mogu biti u obliku pojedinačnih ravnih valkana ili u pletenom obliku. Čimbenici o kojima ovisi čvrstoća vlaknima ojačanih kompozita jesu smjer vlakana, množina vlakana, obloženost vlakana organskom smolom, svezivanje vlakana s organskom smolom, te sama svojstva valkana i organske smole. U restaurativnoj stomatologiji upotrebljavaju se vlakna s jednostrukom, dvostrukom i višestrukom usmjerenošću. Vlakna imaju ulogu učvrsne osnove samo u onim slučajevima u kojima se sila opterećenja prenosi s kompozitne osnove na vlakna. U slučaju nastanka pukotina i stvaranja praznoga prostora između vlakana i kompozitne osnove, smanjuje se sposobnost primanja opterećenja. Nedostatna obloženost vlakana organskom smolom uzrokuje probleme povećanoga zadržavanja vode. To slabi mehanička svojstva i/ili stvara nakupine kisika što inhibira radikalnu polimerizaciju organske smole, a time i nastanak ostatnoga monomera od čega može nastati upalna reakcija na sluznici usne šupljine. Novi vlaknima ojačani kompoziti mogli bi biti sredstvo izbora za izradbu udlaga, bezmetalnih i nekeramičkih nadomjestaka s izvrsnom estetikom i dugotrajnošću nadomjestka.Fiber reinforcement has been discussed in the dental literature since the early 1960s, althogh the more recent availability of commercial products is only now leading to recognition and general clinical use. Fiber-reinforced composite can be described by fiber type and fiber orientation, in addition to the presence or abscence of preimpregantion with a resin. Polyethylene, glass, kevlar and carbon fibers have all been used in either unidirectional or woven fiber orientations. The factors affecting the strength of fiber-reinforced composite are orientation of fibers, quantity of fibers, impregnation of fibers with the matrix polymer, adhesion of fiber to the matrix polymer, properties of fibers vs. properties of matrix polymer.In dental reconstructions, undirectional and bi- or multidirectional fiber orientation is used. Fiber reinforcement is only successful is the loading force can be transferred from the matrix to the fiber. In the case of voids between the matrix and the fiber, the load-bearing capacity of fiberreinforced composite decreases. Poorly impregnated fibers cause another proble: increase in water absorbtion, which reduces the mechanical properties, and oxygen reserves, which inhibits radical polymerization of the polymer matrix and increases the residual monomer content which can lead to irritant reactions in the oral mucosa. A new fiber-reinforced composite provides the potential for fabrication of splints, metal-free, ceramic-free prosthesis with potential for long-term durability and excellent esthetics

Possibilities of the Application of Fibre Reinforced Composites in Implantological Therapy

Vlaknima ojačani kompoziti (engl. fiber reinforced composites, FRC) posebna su skupina materijala sastavljena od kompozita u koji je uložena određena vrsta vlakana. Vlakna se razlikuju po kemijskome sastavu i po načinu izradbe. S obzirom na kemijski sastav, danas se u restaurativnoj i estetskoj stomatologiji najčešće rabe polietilenska i staklena vlakna (osim te dvije vrste mogu se naći ugljična i kevlar vlakna). Prema načinu izradbe vlakna mogu biti istosmjerna ili pletena. Pletena vlakna međusobno se razlikuju po veličini i načinu pletenja. Uporaba vlakana u svakodnevnom kliničkom radu posljednjih godina sve više dobiva na važnosti. Svoju uporabu našla su u gotovo svim dijelovima stomatološke struke: parodontologiji, restaurativnoj stomatologiji, traumatologiji, ortodonciji, itd. Vlakna mogu biti izrađena u dva osnovna oblika: preimpregnirana i neimpregnirana. Preimpregnirana vlakna u posebnom su načinu pakiranja i već obložena kompozitnom osnovom, a kod neimpregniranih vlakana potrebna je predpriprema prije ulaganja u kompozitni materijal. Uporaba vlaknima ojačanih kompozita otvorila je nove mogućnosti u rješavanju određenih problema koji mogu nastati tijekom implantološkoprotetske terapije. Cilj je predavanja prikazati mogućnosti upotrebe vlaknima ojačanih kompozita u različitim kliničkim slučajevima te uputiti na pogrješke tijekom kliničke izradbe.Fibre reinforced composites (FRC) are a specific group of materials consisting of composites in which determined types of fibre are inserted. The fibres differ according to their chemical composition and method of construction. With regard to the chemical composition, polyethylene and glass fibres are most frequently used today in restorative and aesthetic dentistry (apart from these two types, carbon and kevlar fibre can be found). According to the method of construction the fibres can be parallel or plaited. Plaited fibres differ mutually with regard to the size and method of plaiting. In the last few years application of fibres in daily clinical work has become increasingly important. Their application has been found in almost all areas of the dental profession: periodontology, restorative dental medicine, traumatology, orthodontics, etc. The fibres can be constructed in two basic forms: impregnated and unimpregnated. Impregnated fibres are packed in a special way and already coated with the composite base, while in the case of unimpregnated fibres prior preparation is necessary before insertion in the composite material. The application of fibre reinforced composites has opened up new possibilities in the treatment of specific problems which can occur during implantological-prosthetic therapy. The purpose of the lecture is to show the possibilities of the application of fibre reinforced composites in different clinical cases and to describe possible errors during clinical construction

Alterations of FHIT and P53 genes in keratocystic odontogenic tumor, dentigerous and radicular cyst

BACKGROUND: The purpose of this study was to determine fragile histidine triad (FHIT) and p53 protein expression, and to analyze FHIT and p53 gene status in keratocystic odontogenic tumor (KOT), dentigerous cysts (DC) and radicular cysts (RC). ----- METHODS: The methods used were immunohistochemistry and molecular genetic methods including loss of heterozygosity (LOH) and gene sequencing. ----- RESULTS: FHIT protein expression was different among groups. Aberrant expression was the highest in KOT, then in RC and DC. p53 protein expression was different among groups. LOH in paraffin-embedded specimens was detected in 22.6% and 12.9% for FHIT and p53 respectively. Mutation of p53 gene at codon 237 was observed in only two specimens (one KOT and one DC). Of the six frozen specimens, three exhibited FHIT gene LOH (two RC and one KOT). KOT showed loss of exons 6-7 at FHIT locus and mutation at codon 237 at p53 locus, but this could be a chance result. ----- CONCLUSION: Aberrations of FHIT and p53 genes/proteins could be considered markers responsible for the development of odontogenic lesions

Three-Rooted Maxillary First Premolars: Five Clinical Cases

Prvi gornji trokorijeni pretkutnjaci ne pojavljuju se često, ali njihovu pojavnost moramo imati na umu pri endodontskom tretmanu gornjih pretkutnjaka. Ulazi u bukalne korijenske kanale obično nisu dobro vidljivi, pa unatoč dobrom poznavanju anatomije, kliničkom iskustvu i radiografskoj snimci jedan od bukalnih kanala ostaje neobrađen. Incidencija prvih gornjih pretkutnjaka s tri odvojena korijena, tri kanala i tri apeksna otvora je između 4-6%. U radu je prikazano 5 endodontskih liječenja prvih maksilarnih pretkutnjaka s 3 korijenska kanala. Prvi slučaj je liječenje zbog protetske indikacije gdje su odmah uočena i tretirana sva 3 kanala, što je radiografski dokumentirano. Preostala 4 slučaja su retretmani jer prijašnja liječenja nisu bila uspješna zbog neprepoznavanja i netretiranja trećega kanala. Učinjeni retretmani radiografski su kontrolirani.Three-rooted maxillary first premolars do not occur usually, but their possibility always has to be considered. The buccal orifices of the root canals are not clearly visible. In spite of a good knowledge of tooth anatomy, clinical experience, and X-rays, the third canal is often overlooked. The incidence of maxillary first premolars with three roots, three canals and three foramina is about 4-6%. In this article 5 clinical endodontic cases of first maxillary premolars with three canals are presented. The first case presents endodontic treatment of the first right maxillary premolar for a prosthetic reason. All three canals were recognized and treated as documented by radiographs. The remaining cases were retreatment of the first maxillary premolars where third canals had remained unrecognized during previous endodontic procedures, resulting in failure of treatment. Retreatments were performed and results documented by radiographs

Postendodontic Tooth Restoration - Part I: The Aim and the Plan of the Procedure

Endodontskim zahvatom uklanjamo pulpu, nekrotičan dentin i dio zdrava tvrdoga zubnog tkiva. Time smanjujemo otpornost preostala zubnoga tkiva na sile vlaka i tlaka koje nastaju pri okluzijskim dodirima zuba. Zato restaurativna opskrba endodontski liječena zuba mora zadovoljiti zahtjeve retencije restorativnoga nadomjestka, otpornosti nadomjestka i zubnoga tkiva na sile unutar žvačnoga sustava, dobra koronarnog i intraradikularnoga brtvljenja te estetske zahtjeve. Poslijeendodontska opskrba uključuje sljedeće postupke: nadoknadu izgubljena zubnoga tkiva aloplastičnim materijalima u izravnoj ili neizravnoj izvedbi (ispunom amalgamom, kompozitom, stakleno ionomernim cementom, ili izradbom inleja, onleja ili overleja); uporabom intrakanalnih i parapulpnih kolčića uz nadoknadu zubne krune aloplastičnim materijalom; izradbu batrljka zuba aloplastičnim materijalom s uporabom intrakanalnih i parapulpnih kolčića ili bez njih uz nadoknadu zubne krune protetskim nadomjestkom; laboratorijski izrađenom nadogradnjom uz nadoknadu zubne krune protetskim nadomjestkom. U nekim slučajevima bit će dovoljno samo zabrtviti pristupni kavitet nekim od aloplastičnih materijala, a u drugim bit će potrebno osigurati okomitu stabilizaciju preostaloj kruni u obliku intraradikularne nadogradnje i izraditi protetski nadomjestak. Izbor postupka ovisit će o stupnju razorenosti zubne krune, smještaju zuba u zubnome luku, okluzijskim dodirima zuba, morfologiji korijenskih kanala, funkcijskim i estetskim zahtjevima, materijalnim mogućnostima te o vremenu koje imamo na raspolaganju. Pravilno prepoznata indikacija uz poštivanje svih faza izabranog postupka poslijeendodontske opskrbe osigurat će opskrbljenom zubu punopravnu ulogu u stomatognatom sustavu.Endodontic procedure requires removal of the pulp tissue and necrotic dentine, as well as a significant amount of healthy hard dental tissue, which results in reducing the resistance of the tooth to the occlusal loading forces. Restoration of such a tooth needs to satisfy requirements for retention of the restorative material, its resistance, as well as the resistance of the remaining dental tissue to occlusal forces, good coronal and intraradicular obturation and also aesthetic requirements. Postendodontic treatment includes the following procedures: replacement of lost tissues using alloplastic materials directly or indirectly (amalgam, composite resin and glass-ionomer cement fillings or inlay, onlay or overlay restorations); the alloplastic material crown restorations using intracanal posts and parapulpal pins; the alloplastic material core buildup with or without intracanal posts and parapulpal pins covered with prosthetic crown; restoration of lost tooth structure using laboratory made post and core covered with prosthetic crown. Sealing of endodontic cavity using one of the alloplastic materials would be the treatment of choice in uncomplicated cases, whereas in severely damaged teeth ensuring remaining tooth structure by vertical stabilization and the prosthetic crown would be necessary. The choice of procedure depends on the severity of crown damage, the tooth position in the arch, occlusal contacts, morphology of root canal spaces, functional and aesthetic aspects, financial ability and available time for performing the procedure. The correct indication evaluation respecting all steps of the chosen procedure will provide long term survival of the postendodontically treated tooth in the stomatognathic system

Surgical Treatment of Neuralgia as a Result of Ossification of the Mental Orifice

Prikazan je slučaj bolesnika s osteomom donje čeljusti koji je svojim rastom izazivao kompresiju mentalnoga živca i neuralgiformne boli. Intraoralnim pregledom nisu nađeni koštani deformiteti čeljusti, a dijagnoza je potvrđena rentgenskim nalazom, što govori da se radi o enostozi ili središnjem osteomu. U prikazu je opisana i operativna tehnika eksterne dekompresije kojom je epineuralna ovojnica živca oslobođena od pritiska nastalog rastom benigne koπtane tvorbe. Šest mjeseci nakon zahvata pacijent je bio bez simptoma, s normalnim senzibilitetom u donjoj čeljusti i urednim rentgenskim nalazom.A case of a patient with osteoma of the lower jaw is presented. Osteoma caused compression of the mental nerve and neuralgiform pain. During an intraoral examination, osseous deformity of the mandibula was not found. Diagnosis was confirmed by X-ray, which showed enostosis or a central osteoma. The presentation describes the surgical technique of external decompression by which the nerve epineural integument is released from the pressure caused by the benign osseous formation. Six months after the surgery the patient had no symptoms and had normal sensibility in the lower jaw and no irregularities

Reasons for Extraction of Permanent Teeth in Urban and Rural Populations of Croatia

The survey aimed to determine the reasons for extraction of permanent teeth by general dental practitioners in urban and rural population of the Senj region, Adriatic coast, Croatia. During a two-year period (1998–9), a total of 2006 teeth were extracted in both regions, in patients aged 15+. The causes were defined as follows: (1) decay or root without a crown (radix relicta), (2) periodontal disease, (3) endodontic or periapical diseases and (4) other reasons – orthodontics/prosthodontics and dental trauma. The statistical Chi-square-test was used to determine the significant difference between the populations and the sexes. Dental caries was the most frequent cause for extraction (over 50%), followed by endodontic and periapical diseases (23%) as the result of untreated caries and at the end periodontal disease (21%). Urban population more often lose teeth due to periodontal disease (22.75%) than rural (18.93%, p<0.05). Similarly, this is more frequent in the urban male population (25.61%) than the female urban population (20%, p<0.05). In rural areas, people more often lost teeth as a result of endodontic and periapical disease (25.85%) than in the urban locations (19.07%, p<0.01) and this is more frequent in women from rural areas (28.37%) than the rural men (22.44%, p<0.05). Periodontal disease was not the main cause of tooth loss in either the rural or the urban population. Dental caries and its sequel remain the most important challenge for the dental service. It also reveals the inadequacy of dental services. Education of both the population and the general dental practitioners must be conducted in order to improve oral hygiene and to insist on conservative rather than extraction therapy

Possibility of the Application of CO2 Laser in the Prevention of Demineralisation of the Enamel

Krune gornjih srednjih sjekutića prepiljene su uzdužno dijamantnim diskom na dva jednaka dijela. Na istom zubu labijalna ploha jedne polovice je obasjana CO2 laserskom zrakom (15 W; spot 3,5 mm; 6 pulseva u trajanju od 0,5 sek.), a druga polovica korištena je kao kontrola. Na labijalnim plohama ostavljeni su prozorčići veličine 3 x 3 mm, a sve preostale plohe polovica pokrivene su plavim voskom. Uzorci su eksponirani djelovanju demineralizirajuće otopine (0,2 M otopine natrijevog acetata i 0,1 M mliječne kiseline) kroz 10 dana. Količina otopljenog kalcija određivana je atomskim apsorpcionim spektrofotometrom. Količina otopljenog fosfora određivana je po Loweyu fotometrijskim kolorimetrom. S obasjanih površina otopljena je statistički vjerodostojno manja količina kalcija (p<0,01) u odnosu na kontrolnu grupu. Otopljena je i manja količina fosfora, ali bez statistički vjerodostojne razlike u odnosu na kontrolnu skupinu.Tooth enamel laser irradiated under certain conditions previously has been shown to have reduced subsurface demineralizations rate. The teeth were cut vertically in half with a thin diamond disc. One half of each tooth served as a control and the other half was irradiated using the CO2 laser. Laser energy was applied at incisive labial surface (15 W, 0.5 s, spot size 3.5 mm). After irradiation the specimens were coated with wax leaving only the windows 3 x 3 mm on the labial surfaces. After experimental demineralisation with 0.2 M sodium acetate and 0.1 M lactic acid solution for 10 days, dissolved calcium and phosphorus were analyzed in the demineralizating solutions using atomic absorption spectrofotometry and colorimetric method (method described by Lowey), respectively. Ca and P concentrations in demineralizing solutions per unit surface area were lower then the controls

Efficiency of Polylactide/Polyglycolide Copolymers Bone Replacements in Bone Defects Healing Measured by Densitometry

Healing of bone defects is the most frequent cause of failure in surgical treatments of an odontogenic ostitic processes. The aim of this study was to determine successfulness in healing of bone defects after implantation of alloplastic co-polymer-polyglycol bone implant. A group of 45 cases with periradicular ostitic processes were examined. The densitometric measurements were taken from radiovisiographic dental x-ray images. Patients were observed throughout a period of one year. The results obtained were analyzed and presented graphically. Thirty-eight patients (84%) were treated successfully, and seven patients (16%) showed unsuccessful healing of the bone defects. The results obtained indicate that polyglycol copolymer bone implants can be successfully used in a treatment of odontogenically caused bone defects. Their fundamental advantage is a slow biodegradation, which ensures a more suitable area for the apposition of a new bone in the defect, simple application in clinical work and the possibility of a mutual combination of all three available forms

Postextraction pain treatment possibilities

Postekstrakcijska bol je komplikacija koja se javlja nakon vađenja zuba. Najčešće nastaje u molarnoj regiji donje čeljusti. U ovome radu uspoređene su dvije metode liječenja postekstrakcijske boli: konzervativna i kirurško - konzervativna metoda. Svrha rada bila je odrediti najdjelotvorniji način liječenja te komplikacije. Istraživanje je provedeno na trideset pacijenata sa simptomima postekstrakcijske boli. Petnaest pacijenata liječeno je konzervativnom metodom, a petnaest kirurško - konzervativnom metodom. Pacijenti su klinički praćeni do prestanka simptoma. Dobiveni rezultati pokazuju da je kirurško - konzervativna metoda liječenja djelotvornija jer u kraćem vremenu smiruje simptome boli.Postextraction pain or alveolitis sicca dolorosa is a complication which appears after tooth extraction, usually in the molar region of the lower jaw. In this paper two methods were compared: conservative and surgical-conservative method. The research was carried in order to establish which method is more advantageous and more effective. The pain treatment lasted for one year. Thirty patients were treated and each of them were separately conducted during three weeks after the treatment. Fifteen patients were submitted to conservative therapy, and fifteen others to surgical-conservative therapy. The results (tables and charts) show that both methods are effective and that both methods lead to symptom termination. However, surgical- conservative method appeared to be more effective, because in the first seven days after the therapy, approximately 75% of the patients no longer had alveolitis symptoms