Abstract no. 109published_or_final_versio

Ishigami, K

Low, D

Swain, MV

Takeda, T

Journal of Dental Research

HKU Scholars Hub

Title Ultra-micro indentation characterisation of mouthguardmaterialsAuthor(s) Low, D; Swain, MV; Ishigami, K; Takeda, TCitation40th Annual Meeting of the International Association for DentalResearch (Australia & New Zealand Division), Perth, WesternAustralia, 2-5 July 2000, v. 80 n. 4, p. 975Issued Date 2001URL http://hdl.handle.net/10722/53668Rights Creative Commons: Attribution 3.0 Hong Kong LicenseJ Dent Res 80 (4) 2001 Divisional Abstracts: Australia/New Zealand Division 975Two fibronectin-binding protein genes detected in viridans streptococci 'g Oral halth of remote-dwelling W.A. Aborigines.1 bacteraemnia isolates. 1 2 CM STBS,PJ RIORDAN. Comnty Dental Services, Metropolitan HealthAR HOLMES'. GHW BOWDEN', RM LOVE". (I University of Otago, Dunedin, New Service, Perth, W. Australia.Zealand, 2 University of Manitoba,Winnipeg, Canada).ObetvanBakrudTeCSpoisannulvstngetlsrictoomOral stTeptococcal species are increasingly isolated from cases of bacteraemia, Objreotie AndrigBalckgroundithesCiS prvieste anAnustalWvsTin dsentalservice torsomparticular in cancer patients, and are also imnplicated in infectious endocarditis. A rmt brgnlcm uiisi etmAsrla(A.T seti ed,oamechanism whereby these normally commensal bacteria might dissem-inate from an health status of Aborigines in 18 communities in the Kimnberley and Pilbara regionsorally colonised site may be via adherence to extracellular matrix (ECM) proteins, such was surveyed in 1997 and 1999. Methods Clinical examinations, conducted by dentists,as fibronectin (in), exposed during chemotherapy treatment. The CshA polypeptide of included all available schoolchildren, and adults who wished to have a dental check-Streptococcus gordonii is the only identified in-binding protein of a viridans up. Exams (WHO criteria) were conducted in health centres using standardisedstreptococcal species (McNab ctlat., 119991)J Bacteriol, 181:3087-3095). We have detected hhigadpral etleupeth idns eoddo pca oi,wrhomologues of cshA and a Streptococcus pyogenes in-binding protein gene, FBP54, in lgtiangfeand tcoportaberod ntalyeqipment. The findngs,recordedhonh arspeciaoform, wereWlaboratory strains of the viridans streptococcal species, Streptococcus sanguis, trasfrrdDetol computer forvanaysiandfrareuomardsittheNtoaO raHesults ofuthey 19987/WAStreptococcus oralis and Streptococcus mifis. In order to investigate whether such proteins ChiuldsDhenta Healt Survey%11andfo7auls the5 Nationd(al ora HeatheSurey (1987/8).tare involved in pathogenesis, it first needs to be shown that the eshA and FNBP54 gene RslsTeewr 3-,9 11 n 455 rod dt nohraegop ohomologues are consistently present in clinical isolates. Thirty three blood isolates reported here). Among 5-7 yr olds, dmft was 2.6 (1.4 in WA 6-yr-olds) and among 11-from cancer patients undergoing chemotherapy were obtained and were identified to 13 yr-olds. DMFT was 1.7 (0.8 in WA 12 yr-olds). Mean DMFT in adults was 5.1the species level by use of standard biochemidcal and physiological tests and typed by whereas in Australian adults mean DMFTIwas 18.1. The examined Aboriginal adultsribotyping. The majority (>80%) of the isolates were identified as either S. mitis or S. had on average 26.6 teeth present (Australia adults 21.1 teeth). Conclusions Aboriginaloralis. Using the Polymerase Chain Reaction (PCR) technique and Southem blotting c-hildren have poore oral health than the state average but Aboriginal adults' carieswith S. gordonii probes, FNBP54 and cshA gene homologues were identified in all S. ttsi etrta h ainlaeag.Teefnie r ossetwtoralis and S. mitis clinical isolates. The genes were also detected in untyped isolates. In sau sbte hntentoa vrg.Teefnig r ossetwtconclusion, we hav confirmd the presence of homolgues of two genes encoding hypothesis that canies nisk factors are greater for today's young Aboriginals than wasputative fibronectin-binding proteins in viridans strpooclbacteraemia isolates. the case when today's adults were children; this is a cohort effect.this work was supported by- thie University of Otago.O9 Ultra-micro indentation characterisation of mouthguard materials. .a Effect of disinfectant on dimensional accuracy of alginate impression material.19 D LOW", MV SWAIN', K ISHIGAMI', T TAKEDA' 1 Biomaterials Science Research 113 DLOW, T SUMII' and MV SWAIN. BiomateriaLs Science Research Unit, The UniversityUnit, The University of Sydney, Australia, 2 Department of Research for Sports of Sydney, Australia.Dentistry, Tokyo Dental College, Japan). Maintaining dimnensional accuracy of dental imnpression miaterials during disinfectionMouthguards play an important role in preventing dental trauma. However, the literature on is important. The present shady was aimed to investigate the effect of variousmechanical properties of mouthguard materials is limited. The present study was designed to disinfectant solutions on the dimensional accuracy of an alginate impressionevaluate elastic-plastic properties of the materials. Three bands of mouthguard materials (clear material. Two grooves separated by a distance of 50,000 m were carved on a plasticand coloured) were selected. An ultra micro-indentation system (UMIS-2000, CSIRO) to reference plate from which alginate impressions (Palgat Plus, ESPE) were taken. Thedetermine near surface properties of materials with nanometer resolution. Each measurement distance apart of the same groove was measured on the resultant impressionconsisted of at least 10 indentations. The measurement procedure was programmned such that following or exposure to the various disinfectant solutions. The measurements in air,the specimens were first indented to maximum force of either 40 or 50 inN. All the indentations immediately following the taking of an impression were taken as the referencewere equally spaced (250 in). Each measurement was conducted with a spherical stainless dimnension, were compared with the measured lengths of the various disinfectantsteel indenter (R = 500 tim). Typical contact pressures were - I MPa. The elastic modulus value solutions. Measurements in air at 6 and 60 minutes were also taken and were foundCE) at maximum depth and the energy loss ratio during loading and unloading is given by so be 49.795 and 48,%7 mo respectively that using a precision travelling microscope.Wi/WI where WI is the area under the loading force displacement and Wi is the area between Experiment was repeated 5 times with 2 measurements for each specimen. Statisticalthe loading and unloading curves. The higher the ratio, the greater energy absorption capacity signsificance (f-test) was set at p<0O.05of the system. The E values (mean ± SD) in GPa and Wi/WI in % are summarised in the Table Air Water Milton Novasonicsbelow. All materials gave significantly different E values between clear and coloured specimens 50,094 ± 2' 6 minutes 50.091 ± 37' 50,100 ± 42' 50,082 ± 140(p<0.001, t-test) - 60 miinutes 50,054 ± 22"- 50,005 ± 66-- 50,058 ± 34"-EC PC SH EB PB SB There is no significant difference between various solutions in 6 and 60 minutes timeE (MPa) 15.93 ± 0.09' 19.45 ± 0.07" 15.10 ± 0.11' 17.33 ± 0.14 b 17.72 ± 0.13' 17.17 ± 0.42' intervals. Of all the disinfectant solutions examined, 6 minutes disinfection withWi/Wt(%) 11.48±0.16 12.08±0.15 11.33±0.07 12.46±0.17 11.83 ±0.17 11.26 ±0.08 Novasonics had demonstrated mintimum dimensional change (12 in). WhilePresent UMIS system was reliable and consistent for quantity the elastic modulus and energy exposure to Milton solution for 60 minutes had shown the greatest dimensionalloss during indentation process of mouthguard materials, change (89 in). A minimnum distorted impression would be maintained after6minutecs..disinfection, 'This study was supported by the Novapharmn Research(Australia) Pty Ltd.Application of the focused ion beam in dental research. 4 A Dimensional stability of alginate impression material when powdenwaterratio is11 0 H NGO', M MORRIS"*, I CAIRNEY', P.MUNROE', M VAGAS' and G) MOUNT'. I 114? varied.ClaeAustralian Clinical Dental Research Centre, School of Dentistry, The Q BUt. M TANG, M WANG, A YAU, C THOMAS-. Paculty of Dentistry, University ofColgate~~~~~~~~~~~~~~~~~~~~~~~~~~Sydney.Australia.University of Adelaide, Adelaide, Australia, 2 Electron Microscopy Unit, The The clinical practice of altering the consistency of alginate imnpression material byUniversity of New South Wales, Sydney, Australia, 3 Department of Operative varying the powder-water ratio to meet different circumstances has proved veryDentistry, The University of Iowa, Iowa City, USA. useful. The dimensional stability of the various consistencies however needed to beFocused Ion Beam (FIB) technology has been available for over ten years but until investigated because no manufacturer actually recommuends the practice and a studyrecently its usage has been confined to the semxiconductor industry. It was developed was set up to test seven specimens each of a light, medium and heavy consistency,originally as an imnportant tool in that industry for defect analysis and circuit stored dry and wet. Water:powder ratios were derived from clinical experience ofsuitable consistencies and then standardized for all specimnens as was the mixing bymodification and, more recently, for preparation of sasmples for viewing under the electronic mixer. Specimnens were prepared in a cylindrical mold (12mm diameter x 20transnmission electron midcroscope. Its ion and electron imaging modes complement the mmn) and after a set setting time transferred to a transducer-containing measuringscanning electron microscope and it is possible to prepare samples from a wide range device, recording dimensional changes via a data logger. Each specimen was testedof materials and to allow detailed study of many types of adhesive interface. FIB allows over 40 mmn, both dry and wet, the wet specimnens surrounded by wet cotton wool. Allof th are of nterstad prcisemillig wih miimalasmpe deormaion.specimens contracted (indicated by means) and the average readings for 7 specimensselection ofteae fitrs n rcs Wn ihmnmlsml eomto.were: dry; heavy. - 2.23% (±0.484). medium, - 2.42% (±t0.675), light. - 3.17%/ (±r0.508);The aimn of this paper is to introduce FIB into dental research and to demonstrate its wet; heavy. - 0.32% (± 0.113), medium, - 0.22% (± 0.268). light. - 1.08% (± 0.141).application in examining the dental restorative material interface. The example offered Statistically compared all dry specimens differed significantly from wet (p = 0.0001. p=involves the characterisation of the interface between the composite resin used to repair 0.000, p = 0.0000) but medium compared with heavy wet and dry were nota secton ofporceainfacturd fro a crwn ora brige. I is sggestd tha thissignificantly different (p = 0.37 and 0.56). Shrinkage was found in all six categories ofspecimens in time. Alginate stored dry contracted much more than wet but heavy andinstrument offers opportunities to expand research in dental materials to areas not medium consistencies displayed similar shrinkage for both wet and dry and both12ossiblehefnr=,.This work was gratefully supported by ESPE Australia P/L. shrank much less than the light. It is postulated that clinically significant shrinkagcould occur after 2.8 min. and that fth recomnmended traditional 10 min, storage periodmay be excessive. However, as light bodied alginate is used only in nareowdiesosthe Quite high shrinkage is not in fact mprtnPerceptions of dental attractiveness in UK and Malaysia. Humanbuccal epithelium and vaginal epithelium: a comparative study.JC SETCOS', P HAMEED, M MANNAN, T MACPARLANE, CG TON', NHF WILSON. I1 IO HOMPSON-, P VAN DER BIJL. CW VAN WYK, AD VAN EYK. Paculty ofDental Schools, University of Manchester, United Kingdom and I University of Malaya, Dentistry. University of Stellenbosch, Tygerberg 7505, South Africa.Kuala Lumpur, Malaysia. Vaginal mucosa, in contrast to buccal mucosa, is more readily available. If the formner could beThere m-ay be variations in what is considered to be a pleasing dental appearance substituted for the latter, it would expedite research involving the buccal mucosa. Both arebetween dentists, non-dentists and different ethnic groups. Objectives: To determidne if lined by non-keratinized epitheliumn, the distribution of their keratin filaments is comnparablethere were differences in perceptions of dental attractiveness between subjects of and their permeability to chemical substances is similar. To further strengthen the concept thatvarious groups and in two different countries. Method: Ten standardised photographs vaginal epithelium could replace buccal epithelium in certain studies, comparisons areof full arches of mainly non-restored teeth, generally well-aligned and in occlusion, necessary with regard to the thickness, patterns of keratinization, the presence or absence ofwith the ips retrcted,w shown o 275 detal and atientintercellularnchlipidintmeellueaandpitheaelipidacompositioncomofst theo pitheepiahli Becaecueethesewit theNlips5retactd,wr tomur27Mdnalayi paint=suject ianMncWhestner,U characteristics all play a role in the permeability of substances through the epithelial layer, theyUK (MA, n=10)andKualaLumpur Malasia (K, n=15). Man-Whiney-U were examined and compared. Thirty-three specimens of vaginal mucosa fromstatistical tests evaluated the mean rankings comparing MAN and KL, and between postmenopausal women and 36 of buccal mucosa were investigated. To compare thickness, thedental and non-dental groups in each of MAN and KL. Kruskal Walls tests were used cell layers in sections of each mucosal specimnen in the 3 thickest and 3 thinnest regions were

Ultra-micro indentation characterisation of mouthguard materials

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Ultra-micro indentation characterisation of mouthguard materials

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