School of Oral Health Sciences
Permanent URI for this communityhttps://wiredspace.wits.ac.za/handle/10539/18724
Browse
8 results
Search Results
Item How well do fourth year Wits Dental Students place resin composite restorations?(2003) Lightfoot, J.; Clarke, F. M.; Grossman, E. S.OBJECTIVES:To evaluate, by means of a scanning electron microscope (SEM) the quality of resin composite restorations, placed as a first attempt by fourth-year dental students. METHODS: Ten Class IV direct composite restorations, placed in plaster-mounted extracted incisor teeth as part of pre-clinical course requirements, were selected. Specimens were evaluated and graded on a two-point scale by a staff member according to departmental clinical evaluation criteria. Five restored teeth were prepared for surface evaluation of marginal integrity, surface roughness and contour using SEM. The remaining specimens were embedded in resin and ground down transversely, parallel to the incisal edge until a dentine core was apparent. The ground surfaces were polished, prepared for SEM and assessed for etched layer, placement of bonding agent, composite adaptation and overall consistency. RESULTS: Clinical assessment and SEM surface evaluation correlated favourably for all criteria, except contour, indicating that students were reasonably competent in finishing techniques. Ground samples revealed acceptable etched enamel layers and marginal adaptation. Bonding agent thickness varied between 0 and 200 microns casting doubt on procedural accuracy. Porosities and voids were apparent within the resin composite. Internal features were the main reason for unsatisfactory grades. CONCLUSIONS: Students placed restoration satisfactorily. They would benefit if able to examine sectioned restorations to understand critical placement techniques which would contribute to resin composite restoration success. A research component can be introduced into the dental undergraduate curriculum by way of similar projects linked to didactic course-work.Item Surface roughness values for resin based materials(2004) Grossman, E. S.; Rosen, M; Cleaton-Jones, P.E; et alINTRODUCTION: Surface roughness of dental restorative materials is most often established with the Ra value obtained using profilometry or by assessing surface topography with the scanning electron microscope (SEM). Both methods should validate each other in confirming surface roughness. AIMS AND OBJECTIVES: The purpose of this study was to compare surface roughness values obtained with a profilometer to the SEM appearance of 6 resin-based restorative materials and assess whether Ra was appropriate as a sole surface roughness measure. Methods Six 5mm diameter specimen discs of Prodigy (Pr); Z100 (Z); Compoglass F (C); Hytac Aplitip (H); Photac-Fil (Pf) and Vitremer (V) were prepared against Mylar strips and stored in distilled water for 14 days. One side of each disc was sequentially polished with Soflex discs to super fine state, the other side remained unpolished. Three surface roughness measurements were made on each surface (n=18) recording Ra, Rv, Rp and Rt values, this data was subjected to a four way ANOVA and Tukey's Studentised Range Test (p=0.05). Two unpolished and two polished discs per material were prepared for SEM, evaluated and visually grouped for surface roughness. RESULTS: Approximate ascending order of roughness was Z, Pr, H, C, V, Pf for Ra, Rv, Rp and Rt and un/polished treatment. Polishing increases surimens into a "bland" (Pr, H, Z, C) and "textured" group (Pf and V). The polished specimens gave four groups: (Pr), (Z and C), (H) and (V and Pf) of increasing surface complexity. Polishing caused surface scratching, removed the matrix, reduced or removed filler particles and exposed voids within the material. CONCLUSIONS: This study emphasises the importance of using more than one technique to assess surface roughness. Rv and Rp values should be utilised to better understand polish induced surface feature changes. Rv maximum is a better measure to identify surface defects which could affect restoration longevity.Item Comparative cost of ART and conventional treatment within a dental school clinic(2002) Mickenautsch, S.; Munshi, I.; Grossman, E. S.BACKGROUND: The changing oral health needs in South Africa require that both the teaching and clinical techniques of atraumatic restorative treatment (ART) form a part of the restorative undergraduate curriculum. OBJECTIVE: This study was undertaken to establish and compare the estimated costing of an amalgam, composite resin and ART restoration within the Board of Health Funders (BHF) recommended scale of benefits at the School of Oral Health Sciences Oral and Dental Hospital, University of the Witwatersrand (SOHS). METHODS: Fixed and variable costs were calculated by pricing items and equipment used in each procedure. The output values were established according to the recommended scale of benefits (BHF, 1999). This enabled the calculation of contribution margins and net income for each of the three restorations. RESULTS: The annual capital cost for the ART approach is approximately 50% of the other two options (e.g. per multiple surface restoration ART = R1.58; amalgam and composite resin restorative procedures: R3.12 and R3.10 respectively), despite the fact that ART restorations are rendered in a modern dental setting. CONCLUSIONS: Our study shows that implementation of the ART approach within the clinic setting of the SOHS can be accomplished without additional cost. Furthermore ART can be performed as an economically viable alternative to conventional treatment procedures within the clinic setting. The study represents a first step towards determining the cost efficiency of implementing ART as a pragmatic and cost-effective restorative option within the SOHS, University of the Witwatersrand.Item Spreadability of two glass ionomer cements used in Atraumatic Restorative Treatment (ART)(2004) Sindhu, R.; Grossman, E. S.'Press finger' in atraumatic restorative treatment (ART) is used to spread a glass ionomer cement (GIC) to seal the restoration margin and adjacent pits and fissures. This study compared the spreadability of Fuji IX and Ketac-Molar to establish which was best suited for this purpose. Twenty equally spaced cavities (35 mm apart) were machine-cut in each of two Perspex slabs 200 x 100 x 20 mm. Each cavity was 3 mm deep with a 4 mm diameter. Two V-shaped grooves 1 mm deep were cut to traverse the cavities: one 0.5 mm wide, the other 0.25 mm wide. Equal amounts (0.25 ml) of GIC were dispensed, 20 cavities for Fuji IX and 20 for Ketac-Molar and condensed under light finger pressure using a 20 mm diameter cork thinly coated with petroleum jelly. This allowed the GIC to be condensed into the cavity and spread into the differently sized grooves. The samples were stored in deionised water for 24 hours whereafter the length to which the GIC had spread along each groove from the cavity edge was measured to the closest 0.01 mm. The data were analysed using ANOVA and the unpaired Student's t-test (P < 0.05). There was a statistically significant difference between the length of spread of the two GICs (t = 2.534; P = 0.013) which was confined to the 0.25 mm width groove (t = 2.83; P = 0.007) with Fuji IX spreading much further along the groove (10.25 +/- 1.17 mm) than Ketac-Molar (7.66 +/- 4.21 mm). Fuji IX appears to be the better sealant material when selecting for spreadability in ART.Item Surface roughness of aesthetic restorative materials: an in vitro comparison(2001) Rosen, M.; Grossman, E. S.; Cleaton-Jones, P. E.The purpose of this study was to compare the surface roughness of three types of aesthetic restorative material. Six standard samples of two brands of each type of material were prepared namely: hybrid composites (Prodigy, Z100), compomers (Compoglass F, Hytac Aplitip) and glass ionomer cements (Photac-Fil, Vitremer) in a perspex mould (N = 36). Upper and lower surfaces were covered with Mylar strips which, in turn, were covered with glass slides and compressed to express excess material. After light curing, specimens were stored in distilled water for 14 days. Thereafter, one side of each specimen was polished sequentially with medium, fine and super fine Soflex discs (treatment). Untreated surfaces served as controls. All surfaces were examined with Talysurf and the surface roughness (Ra) of each specimen was recorded. Three measurements were made of each specimen. A 4-way ANOVA and Tukey's Studentised range test were used to analyse the data. Statistically significant effects were found for both type of material (P = 0.0001) and for treatment process (P = 0.0065). Among unpolished specimens: Compoglass F is significantly rougher than Vitremer, Z100, Prodigy and Hytac Aplitip, and compomers are significantly rougher than hybrids. Among polished specimens: Photac-Fil is significantly rougher than Z100 but does not differ from Compoglass F, Vitremer, Prodigy and Hytac Aplitip, and glass ionomers are also significantly rougher than hybrids. The smoothest surface is obtained when curing materials against a Mylar strip.Item Bonding agents: adhesive layer thickness and retention to cavity surfaces with time(2001) Grossman, E. S.; Setzer, S.This study assessed bonding agent thickness, cover and the influence of long-term storage on bonding agent retention to enamel and dentine surfaces in cut occlusal cavities in 46 human molar teeth. Two specimens were etched and set aside. The remaining specimens were divided into two equal groups and treated with either Optibond or Scotchbond Multipurpose Plus (SMPP) up to the adhesive stage. Thereafter two specimens from each group were stored for 0, 1, 3, 7 and 14 days and 1, 2, 3, 6 and 12 months in 1% NaCl. After storage the cavity surfaces were examined in a scanning electron microscope (SEM) and scored as to bonding agent cover. One specimen from each treatment was then embedded in resin, two sections prepared midway through each cavity, polished and re-examined in the SEM to measure bonding agent thickness at 13 sites along the cavity surface. Both bonding agents showed highly variable and significant (P < 0.05) bonding agent cover and layer thickness according to cavity site, SMPP more so than Optibond. Pooling of SMPP adhesive was apparent in cavity angles. Mean film thickness was significantly different between Optibond (221 +/- 130 microns) and SMPP (118 +/- 106 microns). There was no significant difference in bonding agent thickness between long- and short-term storage.Item Microscope observations of ART excavated cavities and restorations(2002) Grossman, E. S.; Mickenautsch, S.This in vitro light and scanning electron microscope study examined 39 extracted tooth specimens, hand excavated and restored according to atraumatic restorative treatment (ART), using 'press finger', by 'skilled' and 'novice' operators. Surface features of five excavated cavities, 12 restoration surfaces and the tooth restoration relationships of 22 bisected restored tooth crowns were examined to better understand the clinical effect of the technique. Hand-excavated cavity surfaces were rough with a complex surface arrangement of grooves, crevices, ridges, furrows and overhangs. Enamel and dentine were covered with debris except where surface fractures exposed enamel prisms and occluded dentinal tubules. Ten of the 22 bisected restored specimens had large voids (1-3 mm in length) within the glass-ionomer cement (GIC) restoration or at the tooth-restoration interface. Smaller bubbles (< 50 microns) and irregular shaped inclusions were common in all restorations. Adaptation of the GIC to the cavity margin was extremely variable and easily distinguished from the effects of dehydration shrinkage. It is thought that cavity surface irregularities could cause placement problems making it difficult to adapt the GIC to cavity peripheries. While 'press finger' enabled excellent penetration of GIC into fissures, the technique left restoration surfaces rough. At low magnification, surfaces were irregular; at magnifications higher than X500 scratches, pits, porosities, chipping and voids were evident. However, the 'press finger' technique was able to merge the GIC to a fine edge on the occlusal surface so that the restoration margin was not obvious. No apparent difference was found between the restorations placed by the 'skilled' and 'novice' operators. Tooth-restoration relationships in the ART approach are entirely different to those of traditional restorative techniques. The ART approach requires skill, diligence and comprehension to be undertaken correctly.Item Accurate diagnosis of occlusal carious lesions - a stereo microscope evaluation of clinical diagnosis(2002) Grossman, E. S.; Cleaton-Jones, P. E.; Côrtes, D. F.; et alThis study was undertaken to validate the caries status of 214 teeth by serial sectioning and microscopy after caries diagnosis using four methods. Two hundred and fourteen extracted human teeth with varying degrees of caries were mounted in the jaws of nine training manikins. All tooth surfaces were examined and recorded for caries by four dentists using bitewing radiographs, fibre-optic transillumination (FOTI), mirror alone and a mirror and sharp probe on two separate occasions. Thereafter the teeth were serially sectioned and assessed microscopically for depth of caries lesion on a graded score of 0-7. This report assessed the diagnostic outcome of 2,183 observations for occlusal surfaces. Sound diagnoses predominated over unsound until caries was present in the inner half of dentine. Specificity was between 90% and 95% and sensitivity 26% and 50% depending on which diagnostic method was used and where the sound/unsound threshold was set. Negative and positive predictive values were similarly influenced and varied between 53% and 80% and 73% and 90%, respectively. Probit analysis showed no significant differences (P < 0.05) between examiners and diagnostic methods. Diagnosis of occlusal caries undertaken in an in vitro simulated clinical situation is inaccurate until the caries lesion extends deep into the dentine no matter which of the four methods was used.