Cheng, YY

Chow, TW

Clark, RKF

Wong, DMS

Journal of Dental Research

HKU Scholars Hub

Title Do dry-heat cured dentures fit better?Author(s) Chow, TW; Cheng, YY; Wong, DMS; Clark, RKFCitation13th Annual Scientific Meeting of the International Associationfor Dental Research (Southeast Asian Division), Kuala Lumpur,Malaysia, 1-3 October, 1998, v. 78 n. 5, p. 1178Issued Date 1999URL http://hdl.handle.net/10722/53930Rights Creative Commons: Attribution 3.0 Hong Kong License1178 Divisional Abstracts: Southeast Asian Division I Dent Res 78(5) 199966 Are nitric oxide amid glutamate involved in orofaclal hyperalgeaia? 67 Applications of Cytologic Techniquea in the Diagnosis of Oral MucosalLUHP,YEO J.F. and +LEONGS.L Depaftnenl ofOral & Maxlilfacio. Lesions., TRA.N K. CUC *(Faculty of Odonto-Stomatology- University ofSurgery, 0Departmaent ofAnatomy, National Universliy ofSingapore. Health Sciences,HCM City, Vietnam).This study investigates the role of nitric oxide (NO) and glutamate in the transmission of orofatiat In order to assess the accuracy of cytologic diagnosis techniques compared to histo-hyperalgesia induced by subcutaneous injection of 0.5 ml of4% formalin into the left lateral face of the rat.ptooia ehiu,apopciesuywscrido 2 ainscnutn hT'he pain induced c-fms expressing neurons in the caudal part of the trigeminal nucleus (cSTN) wer pathlgcalCetechiniqeaoC prospcitiv studwreascecancrried ions224 ptientsa cnsutyingteinvestigated for the presence of NO and glutamate receptors, GIuR2/3 and NMDARI1. To demnonstrate NOinCacr enrinH hMnctyfrpcneracrlsosofherlcvty.Fethese neurons, nNOS immTunofluorescence or NADPH-d histochemistry was applied. As preliminary study Needle Aspiration technique (FNA) was performed on nodular and infiltrating lesions (102showed colocalization of the iwo chemicals, NADPH-d histochemistry was used to indicate the presence of cases), and Exfoliative Cytology technique on exophytic and ulcerative lesions (t22 cases) .nitric oxide synthase (NOS). Subsequently, colocalization of NOS/NADPH-d and glutamate receptors,Alcyogidanse wretrafrcnumdby ovninlhsophlgclGIuR2/3 and NMDARI were performned. C-fos labelled nuclei of neurons in the ipsilateral cSTN were located llctogcdiagnosistcnq eusin ucwere phereatersudcnirmued bye fonvenionalhiesulopts ooiamainly m lamma I and outer layer of lammna IL. NOS positive neurons were found mainly as lamina II-IV',digostehquuinpncbooyTesuyisedheflwngrut:around the central canal and in the ventral hem. Very few were observed in lamina I. NMDARI positive - The accuracy of cytologic diagnosis was respectively of 86,2% for FNA and 73,5% forneurons were found in all layers of the cSTN, whereas GluR2I3 positive neurons were encountered miainly in Exfoliative Cytology .the superficial laminae. Confocal laser scaning miicroseope revealed that all c-fos immnunofluorescent nuclei Nocswihflepitvdag sswsobre.were surrounded by NMDARI labelled cytoplasm, most of them by GIuR2I3 and none by NOS. Some c-fos NoFalse-nwaith atfalse-p siti ecdiagnosis was obs rved.d 16 frEfotvponitive neurons were ver close to NOS positive neuroms. NADPH-d was coloc-alized with GluR2/3 orFas-etierewsrspcvlyo 12 frFN an 2,6 frExlaieNMDARI in a smiall population of neurons in lamiina II-IV. Th present study indicates that orofacia =em Cytology.induced c-fos exoresin nernsi the cSTN did not syntheize NO. but could be modulated by NO Both technigues were found to be safe. simRle to perform and accurate for the primarysynthesized and 0diffused from adiacent NOS nositive neurons. It is likely that some of the c-fos nositive diaanosis of oral cancer and Rrecancer lesions . Comgared to excisional bioRsy. they are lessneurons are oMiection neurons Knd the NOS sontive ones are local intemeurons, Most of c-fos &Nitive aggressive and more easily accepted by Ratients, FNA technigue would be recommendedneurons and a small number of NOS zsoitive neurons may respond to sElutamate released from riarafferents thToush NMDA and AMPA recentrs. T7his study is supported by RP3960331 from NUS. for lesions growing in deRth and Exfoliative Cytology for lesions growinsa more in surface.68 Le.CYLW.HMHAG E'(Gaut nttt of O -Ro taio 69 T..CO * ..CHENG, D.M.S WONG and R.K.F. CLARKSciemstea, a 1ndIsanentaion Center,Taipei Medcal CoUegt Taipei,Taiwan, Roc.) (Oral Rehabilitation, University of Hong Kong & UMDS, University of London)The aim of thin study was to develop a new nmethod for detecting fth attaluiest level around teeth, using a Acrylic masin dantures exhibit certain unavoidable dimensional changes. Processingnon-destructive, leas time-comaming and more reliable device. Model Testing and natural frequesscy shrinkage and expansion due to waler uptake are two important aspecta influencing theiranalysis were evaluated to achieve these goasn. Uppercentral incisor was chosen and its finite elenntnmodel dmninlacrc.T netaelna iesoa hne fdnue rcseICP-type Accelermser (PCB Piezotronies, Inc., NY, USA) was attached onto die teste incisor. Impulses by dry and wet heat with different rates of cooling, and at water saturation, fine crosseswere triggeed by ICP-eyp Impulse-Force Teat Hammer (PCB Piezotonics, Inc.) and received by marked on tin-foil inserts were placed at the incisive papilla and tuberosity regions ofAcceleromete. The signala derived from Hammer and Accelerometer weedv taaerdt yai edentulous maxillary casts and incorporated into the dentures during processing. ASignal Analyzer (Prowave Engineering Inc., Taiwan) and natural frequency values were obtained throgh travelling microscope was used to measure the distances between the reference points.Fast Fourier Transfer (FF1) by Signa Docto softwar (Prowave Engnwineeg Co.). Each incisor was tested Water uptake and water content were determined by the mass changes of the denturesthe five times. On the other way, fifteen extrcted upper central iacmanes were used in in vitro experinmet, using an electronic balance. Results showed that dry heat cured and water bath curedThe incisors were fixed by a clamp through a rubber contact. The attachnmen level %wa altered by lowering acrylic resin dentures exhibited similar shrinkage of 0.42 to 0.58% at water saturationthe clamping positioms at 2mm,~4mmn and 6 mmn axually away from cementoenanel junction (CEJ). Finite (95%, Cl). The amounts of water sorption of dentures processed by both methods (0.50elemet methd was then used to simulat and fulfill the in vitro expenimental design. The resulta of in vtsvo and 0.48 mass%) were similar (g5%, Cl) and their associated expansion did not entirelystudy tndicated that the natural frequency of human upper central mattsons rmnped from 710 Hz to 3360 Hz compensate for the 'processing shrinkage. The initial water content of dry heat curedwidi an average of 1701 ± 679 Hz. Lower asehaclet level caused decreased natural frequency values. lIme dentures (1.77 masss%) was unexpectedly higher than that of wet heat cured denturesfinite element analysis showed a linear reatonship (Y = -198.27X + 2523.6, r = -0.99-.p < 0.01 ; X=(16ms%)ThraetwictednuesoldhdnofetonhiraerpakattchentleelaYluvlueofnatra frqunc) btwenphevaleyf)ottbnturl reqenyendvheandintiaowtetcotott(5% Clatatrutaefoidy aduethea credacylitrsiattachmnt level. In conehusisan the naktural frMesecyO Of anuman al wteechnwas 95deCe) Watrhutak ofnsitivewt aatncredacryichesiby: Model Testing Nastural freqency ablssapemt e a nse&d auxiliMr opnittearrsin dentures after deflaskino was in both cases low and the shrinkaae of the dentures at watertosdiina.fieethW,i saturation was similar. The dimensional accuracy of dentures cured by dry and wet heat istherefore similar.SuyobutrProstheses through Vibration Analysis. 71 linical Investigation scan Experimental Gtass lonomaerotzaatiwe: Freliminary Fiadiags.70 M. OK~I*, H. TANIGUCHI, T. INOUE and T. OHYAMA (Tokyo Medical and 71 Y. LUO*, SKHY. WEL M.W. FAN' (Faculty of Denistruty, University of Hong Kong, HongDental University, Tokyo, Japan) Kong, 'School orStomatology, Hubei Medical University, Wuhan, Chins.)Obturator has bonn used extensively in tht functional and esthetic rehabilitation of maxillectomy T'he purpose of this study was to detenmine the safety and efficacy of a new GIC (K-0086) and compare itspatients. The purpose of this study was to evaluate the vibration movement of four types of clinical performance to Fuji IX GP when used in the ART techntique for the restration of posterior primaryobturator in vir. Four bulbs were used in this study: a solid (5), an open hollow (01), a lighster teeth and young permanent tenth. A clinical tria was conducted in December 1997 in Wuhan, China. Theopen hollow (02), and a close hollow (H). The modal analysis of vibration was carried out in order tubject who were aged betwee 6-14 years were chosen from primary school and I secondary school andto find the best form to protect the abutment teeth in the Aramany Class II of post surgical each subject had 1-2 bilateral matched paisr of carious postenior teeth that required either Class l or Claus 1maxillectomy defects. The obturator was excited by the Vibration Generator while the LV-1300 restorations. Atotal of 1327 pupils were screened and 101 bilateral matched pairs ofART restorations wereLaser-Doppler Vibrometer measured vibration at various points. The CF-6400 FFT Analyzer was pLaced in 92 pupils. 55 pairs of restoraions placed'iasnaest teeth were Class I restoratiems; 14 pairs ofused for calculating the frequency response functions, modal shapes and the amplitudes at eah rsraimplaced in primary teeth were Class 1I restorattons. None of the subject dropped oct at themeasurement point and then analyzed on the PC-982IXn personal computer with the Vibrant-Win baselie evaluaton (5-14 days after weaennent). The examinr did not detect any sign or symptoems ofmodal analysis software. T'he results showed the modal shapes were almost the same for 01, 02, hyperseitivit ortaenvitacit rsoranyonadverseefecs Forfathueidretoealationacofdgtw heaperformance,and H types, except for S type at 350-500Hz, while the amiplitudes at the points of the clasps at the cimteresia wecre takes8 Fourfileacphadto stiongher wasgonadfaiuref retoaiond accbrdnFusi theGealuatonenatural frequency (690H4z) for H type were the significantly smallest (momns H: 0.172 ±0.068,5S: for K-0086, and they were all Class H restorations. At the 6 month recall, only one subject dropped out of1.660±0.689, 01:1.780±0.745, 02:0.789±+0.310 mm/Kgf) with ANOVA and Fisher's PLSD (p< the sxtuy. In primary tenth, 16.7% of K-0086 restorations and 93.3% Fuji IX OP rmstorations were0.05). Based on these results, the H DMss obturator would be sugeested in Aramany's Class II classified as 'success'. The failure cases including two fillings having gross defects and a few beingmaxillgar peonsthesis from the point of view of vibration in modal analysis. dislodged in both groups. Nearly all of thse fillings in pensanent teeth were presenit and sound. T'he 6 monthsuccess rates were 98.2% for K-0086 and 100% for Fuji IX GP. There was non statistically significantdifference betwem the two groups in either the permanet tenth or primary teeth. Based on the prelanunaryfinding, it is concluded tha K-0086 may oRrovide a clinical nenformac ggmpamhle to that of Euii DC GPwhich is soeciall manufactured for ART, (This study was partially supported by Dentsply DeTrey.)72 Inhibition of Damilnerallzaton by Restorative Materiab on ArtificIslly Caries 7 Effects of particle-reinforcement on flexural strenpth of RMGIC.Challnged EamuaL ILK_ yIpaa, W.T.C. L,Alhb and RJ. SMALESa1 (apsecady S. MUDAMBI'*, A. YAP', M. Li2 C.L. CHEW and J. NEOt (iNationalat Dentiatry, The Univerity of Hong KOng, bD)partesent of Health, Hong Kong University of Singapore, 2lnStitUte of Materials Research and Engincering,Government) Singapore)ne objetive ofthis sudy wasto effecs of fuoride eleaw f rTheoaaime ofathisonstudyi is tohe determinesthey effectsermofeparticle-reinforcementeinfrconethenth exuraumThojctveo ti usiady wapo assess effctscofy Thuiderelasy f restoratie pmateial on strength of a resin-modified glass ionomer cement (RMGIC). Zirconia oilicate microf'illerdeenineralized enamel, using polnitng microscopy. wereintrThirtyinreceRMdyCextjiacted) aou2d permanent prane6molamremoved for orthodontic reasons were coilected. Standardized coronal buccal cavities (4mm x2mm x 1.s copee5eeitoue noaR GC(uiI C t2 Z) %(4 n %(6mmn) were prepared in these teeth with tungstens carbides #330 in en air uturine handpiece, with water powder weight increase using an ultra-high speed dispersion technique. The manufacturer'sspray. These cavities were restored with two resin-modified GICs (Fuji II and Photac-Fil), two recommended powder: liquid ratio of 3.2g: Ig (control), together with RMGIC mixed atconventional GICs (ChemFil Superior and Fuji IX), a compomer (Dyrac) and a comnposite. (ZIOO) 2% (02), 4% (04) and 6% (06) powder weight increase were used for comparison. Fiveaccording to manufacturers' instructions. The restored teeth were thermocycled and suibsequently placed specimens (25mm x 2mm x 2mm) were made for each group based upon IS04049indedemigseruanlfrzing wsolutiondefeefi fourimeweeks.ls mFluoride releaseifiatinfrome specimensrecurwassngalsoec osealapiredrmiatinthed endeof four weekaL Bucco-lingual planoparallel sections of 100pm were prepared and exunined using a light aeindicationedwatheratpeCimnfore4hcuredusingr20steestheovser-apnrrediationducandwstoredpolamnsing imicosope. end measifetnents were taken using en image analysis software. One-way i itle ae t3" o 4hus lxrlsrnt et eete odce ihaANOVA andTukey-Kramer post-tests were used for analysing any differences in denmiealization among Instron universal testing machine using a I kN load and a cross-head speed of 0.5 men/min.

Do dry-heat cured dentures fit better?

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Do dry-heat cured dentures fit better?

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