Age changes in the mental aperture of experimental animals

Ispitivane su dobne promjene u mentalnim otvorima donje čeljusti u pedeset ženki bijelih lalboratorijsikih Wistar-štokora u dobi od dva do osamnaest mjeseci. Istodobno su analizirane promjene na mentalnom otvoru nakon eksperimentalne lezije živca. Cilj istraživanja bio je odgovoriti na sljedeća pitanja: 1) da li tijekom starenja dolazi do zatvaranja mentalnog otvora zbog odlaganja koštane tvari, 2) da li dolazi do zatvaranja mentalnog otvora nakon eksperimentalne lezije živca, i 3) kakav je histološki nalaz na mentalnom otvoru nakon lezije živca? Rezultati ispitivanja pokazuju da tijekom starenja dolazi do zatvaranja mentalnog otvora u 12% slučajeva kod starijih životinja. To ukazuje na odlaganje koštane tvari u području otvora. Nakon lezije živca ne dolazi do značajnijih promjena na mentalnom otvoru, što govori u prilog hipotezi da je zatvaranje otvora tijekom starenja rezultat primarnog procesa u koštanim tkivima, a ne rezultat atrofije prolazećih živaca. Rezultati su od značenja za tumačenje odnosa neuralnih i koštanih tkiva tijekom starenja donje čeljusti kao i za tumačenje patogeneze neuralgije osteogenog porijekla .We examined age changes in the mental aperture of the lower jaw in 50 female white laboratory Wistair rats between 2 and 18 months old. At the same time, we analyzed changes in the mental aperture after experimental lesions of the nerves. The purpose of our investigation was to answer the following questions: 1. Does the mental aperture close during aging because of the deposition of bony material? 2. Is there a closure of the mental aperture after experimental lesions of the nerve? 3. W hat is the histological finding in the mental aperture after lesions of the nerve? Oiur investigations showed that the mental aperture closed in 12% in older animals, which indicates a deposition of bony material in this area. Significant changes in the mental aperture did not occur after lesions of the nerve which supports the hypothesis that closure of the aperture during aging is the result of a primary process in bony tissue and not a result of atrophy of nerves. Our results are significant for explaining the relationship between neural and bony tissue during aging of the lower jaw and for explaining the pathogenesis of osteogenic neuralgia

Patohistološka slika zubne pulpe nakon preparacije kaviteta visoko-turažnim bušilicama

Histopathological changes occur very rapidly in the pulp when the high-speed drill, which cuts into the dentin, is used. In this investigation, we wanted to confirm possible changes occurring in the histology of healthy, vital pulp within the first thirty post-operative minutes. Six premolars extracted for orthodontic reasons in adolescents between 12 and 17 years of age were evaluated. The teeth were removed and serial sections of the specimen, using classical histological procedures, were made. The histological evaluation under the light microscope revealed changes in the pulp, characteristic for acute inflammatory reaction, that is, hyperemia, extravasation of blood cells and aspiration of the odontoblast in dentin tubulus. We concluded that the turbine drill should be used only on the enamel of the tooth. We recommend using the low speed drill with maximal cold water for work on the dentin. Exposed odontoblastic processus and tubulus should be protected immediately after the preparation of the cavity.Kod preparacija visoko-turažnim bušilicama, koje sežu u dentin, vrlo brzo nastupaju pato-histološke promjene u pulpi. Ovim radom smo htjeli utvrditi moguće promjene u histološkoj slici zdrave, vitalne pulpe, već unutar prvih trideset minuta post-operativno. Koristili smo šest premolara određenih za ekstrakciju iz ortodonskih razloga, adolescenata u dobi od 12 do 17 godina. Zubi su ekstrahirani i načinjeni serijski rezovi preparata, klasičnim histološkim metodama. Histološkom evaluacijom, pod svijetlosnim mikroskopom, smo pronašli promjene u pulpi karakteristične za akutnu upalnu reakciju, tj. hiperemiju, ekstravazaciju krvnih stanica i aspiraciju odontoblasta u dentinske tubuluse. Zaključili smo da u kliničkoj praksi treba turbinsku bušilicu koristiti samo za rad u caklini. Ostale zahvate u dentinu, preporučujemo raditi nisko-turažnim bušilicama uz maksimalno hlađenje vodom. Eksponirane odontoblastičke nastavke i tubuluse potrebno je odmah nakon preparacije zaštititi

The Effect of Chewing Gum in the Prevention of Caries

Zubni karijes je zbog svoje rasprostranjenosti u svijetu velik javnozdravstveni problem. Zbog toga ne iznenađuje činjenica da postoji velik broj materijala i postupaka kojima je svrha prevencija nastanka zubnoga karijesa. Jedan je od tih postupaka uporaba guma za žvakanje koje simuliranjem lučenja sline sprječavaju stvaranje dentobakterijskoga plaka na površinu zuba i uklanjaju već akumulirani plak. Ispitivanje je obuhvatilo 16 studenata (12 studentice i 4 studenta) 3., 4. i 5. godine Stomatološkog fakulteta Sveučilišta u Zagrebu. Mjerena je količina lučenja nestimulirane sline za svakoga studenta, stimulirane sline sa štapićima voska preuzetim iz Caries risk test seta (Shaan, Vivadent) te dvije vrste guma za žvakanje Orbit (Wrigley) Winterfresh i Wild Strawberry. Ispitanici su vosak i gume za žvakanje prvo žvakali jednu minutu i svu skupljenu slinu bi progutali, a zatim su žvakali još tri minute i svu su slinu skupljali u graduiranu menzuru. Dobiveni rezultati su istraženi kao srednja vrijednost i standardna devijacija, a njihova razlika putem student t-testa. Također je izračunan i KEP indeks (DMF/t) za svakog ispitanika. Dobiveni rezultati pokazuju znatan porast lučenja stimulirane sline prigodom žvakanja guma za žvakanje u usporedbi sa žvakanjem voska. Također postoji razlika u lučenju sline u odnosu prema okusu gume za žvakanje. Kod gume za žvakanje s okusom Wild Strawberry volumen sline bio je veći. Rezultati ovog istraživanja potvrđuju opravdanost uporabe guma za žvakanje, pogotovo ako uzmemo u obzir da su većina današnjih guma za žvakaknje zaslađene umjetnim sladilima kao što je ksilitol koji ima i protukarijesno djelovanje.Dental caries, because of its spread worldwide, represents a public health problem. It is therefore, not surprising to find a great number of materials and procedures whose goal is the prevention of its formation. One such procedure is use of chewing gums which stimulate the secretion of saliva, thus preventing the formation of dental bacterial plaque on the surface of the teeth as well as a removal of existing plaque. The study included 16 students (12 female and 4 male) of the 3rd, 4th and 5th year of the Dental School of the Zagreb Universitiy. The goal was to measure the quantity of secretion of unstimulated saliva as opposed to that of stimulated saliva for each student, using the wax sticks borrowed from the Caries risk test set (Schaan, Vivadent) and two kinds of Orbit chewing gum (Wrigley: Winterfresh and Wild Strawberry). The examinees first chewed the wax and the chewing gum for one minute and then swallowed all the secreted saliva. Afterwards they chewed for another three minutes, this time collecting the secreted saliva into a calibrated measuring cup. The achived results are expressed as the medium value and standard deviation, the difference between them being noted with Student t-test. KEP index (DMF/t) for each examinee was also calculated. The achived results showed a significant difference in the saliva secretion during the use of chewing gum and the use of wax. There was also a difference in the secretion of saliva regarding the flavour of the chewing gum. The volume of saliva was more when Wild Strawberry was used. The results of the study justify the use of chewing gums, especially if we take into consideration that many of them contain an artificial sweetner, such as xylithol, with a strong anticaries effect

Aesthetic Reconstruction of Hypodoncy Using Kevlar Fibres

Estetski nedostatak nastao zbog hipodoncije gornjih lijevih pretkutnjaka u pacijenta u dobi od dvadeset pet godina utvrđen je kliničkim i radiološkim pregledom. Tijekom vremena prostor se je smanjio zbog pomicanja trajnoga gornjeg očnjaka u distalnome smjeru na mjesto drugoga gornjeg pretkutnjaka, a nastali međuprostor je odgovarao širini gornjega očnjaka. Minimalnim traumatskim terapijskim postupkom očnjak je nadomješten uporabom kevlar vlakana, adhezijskim postupkom i kompozitnim materijalom.Aesthetic inadequacy due to hypodoncy of the upper left first premolar of a 20 yearold patient was detected by clinical and radiological examination. After a certain period of time space reduction had occurred because of shifting of a permanent upper canine tooth in the distal direction to the place of the second upper premolar, and the gap created corresponded to the width of the upper canine tooth. By a minimal traumatic therapy procedure we substituted the canine tooth by using fibres, adhesive procedure and composite materials

Endodontic system in root fusion of the second lower permanent molar

Makroskopskim promatranjem anatomskih osobitosti korjenova na slučajnom uzorku od 957 ekstrahiranih drugih donjih trajnih kutnjaka ustanovljena je pojava međusobnog stapanja korjenova na 61 zubu. Stapanje korjenova događa se ili na bukalnoj ili na lingvalnoj ili na bukolingvalnoj strani. U skladu sa svojom pojavom dolazi do promjena u anatomskom obliku endodontskog sustava, koji može biti sličan slovu »C«. Promjene u obliku, veličini i dubini pulpne komorice, kao i u obliku i broju korjenskih kanala tijesno su povezane sa stupnjem stapanja korjenova.Macroscopic observation of anatomic root specificities in a randomized sample of 957 extracted second lower permanent molars revealed the occurence of root fusion in 61 teeth. Root fusion was found to take place either on the buccal, lingual or buccotingual side, giving rise to corresponding alternations in the anatomic shape of the endodontic system, which may acquire a »C« like shape. Alternations in the shape, size and depth of pulp chamber as well as in the form and number of root canals thus, appear to be closely related to the degree of root fusion

Incidence of enamel pearls in our population

Promatranjem rasprostranjenosti caklinskih perli na slučajnom uzorku od 7088 ekstrahiranih zubi u srednje-dalmatinskom području utvrđena je pojava caklinskih perli na trideset i osam (1.13%) gornjih i donjih kutnjaka. Dvostruke perle su nađene u sedam zubi (0.21%). Prosječna veličina je iznosila 1.6 mm, a najčešća lokalizacija je bila cerviksna trećina mezio ili distoaproksimalne plohe korijena.Observations regarding the incidence of enamel pearls in random samples of 7088 extracted teeth in Mid-Dalmatia were carried out. Enamel pearls were noticed in maxillary and mandiibulary molars in 38 cases (1.13%). Mean size of anamel pearls was 1.7 mm in diameter, and in most cases they were situated on the cervical third on mesio or disto-aproximal root surfaces. Double pearls were found in 7 cases (0.21%)

Caries and Oral Hygiene in Children in Postwar Novi Travnik (Bosnia and Herzegovina) and Zabok (Croatia)

The study was performed in 1997 and involved school children between the age of 6 and 12 in Novi Travnik, Bosnia and Herzegovina (n = 203) and Zabok, Croatia (n = 132). OHI-S (Simplified Oral Hygiene Index by Green-Vermillion) and DMF (Decayed, Missing, Filled) index were used as main outcome measures. Prewar data were taken from the respective literature. The value of the DMF/dmf (PERMANENT/deciduous teeth) for six-year-olds in Novi Travnik of the period before the war was: d = 5.6, m = 0.4, f = 0.6 and D = 0.3, F = 0.1 and the average DMF index of twelve-year-olds for the same period were 6.5. The DMF/dmf index in 1997 in Novi Travnik was: d = 9.4+/-4.4; m = 0.7 +/-1.1; D = 1.9+/-1.2 and average DMF index of twelve-year-olds was 9.0+/-4.16. The DMF index of twelve-year-olds in Zabok in 1990 was 3.4 and 4.1+/-2.1 in 1997. Total DMF index for all the examined ages in 1997 for Zabok was 6.1+/-3.7 and for the examinees in Novi Travnik 10.5+/-4.1 (p<0.001). Similarly, the OHI-S in 1997 for Zabok was 1.0+/-0.7 whereas 1.7+/-0.7 (p<0.001) in Novi Travnik. In comparison to prewar data, DMF index in 1997 was considerably higher. Increase of DMF index was higher in Novi Travnik than in Zabok, which can be attributed to the war and wartime conditions

Aesthetic Reconstruction of Hypodoncy Using Kevlar Fibres

Estetski nedostatak nastao zbog hipodoncije gornjih lijevih pretkutnjaka u pacijenta u dobi od dvadeset pet godina utvrđen je kliničkim i radiološkim pregledom. Tijekom vremena prostor se je smanjio zbog pomicanja trajnoga gornjeg očnjaka u distalnome smjeru na mjesto drugoga gornjeg pretkutnjaka, a nastali međuprostor je odgovarao širini gornjega očnjaka. Minimalnim traumatskim terapijskim postupkom očnjak je nadomješten uporabom kevlar vlakana, adhezijskim postupkom i kompozitnim materijalom.Aesthetic inadequacy due to hypodoncy of the upper left first premolar of a 20 yearold patient was detected by clinical and radiological examination. After a certain period of time space reduction had occurred because of shifting of a permanent upper canine tooth in the distal direction to the place of the second upper premolar, and the gap created corresponded to the width of the upper canine tooth. By a minimal traumatic therapy procedure we substituted the canine tooth by using fibres, adhesive procedure and composite materials