Research Outputs (Oral Health Sciences)

Permanent URI for this collectionhttps://wiredspace.wits.ac.za/handle/10539/18776

Browse

Author: search.filters.author.et alStart date: 2001

Search Results

Now showing 1 - 5 of 5
  • Thumbnail Image
    Item
    Zinc oxide-eugenol and calcium hydroxide pulpectomies in baboon primary molars: histological responses
    (2004) Cleaton-Jones, P.; Duggal, M.; Parak, R.; et al
    AIM: To compare histological responses to zinc oxide-eugenol (ZOE) and calcium hydroxide (CH) pulpectomies in primary molar teeth with inflamed pulps. STUDY DESIGN:This was an experimental study in 17 juvenile baboons (Papio ursinus). METHODS: Pulpitis was induced with fresh human carious dentine or Streptococcus mutans placed into occlusal cavities in 78 primary molars; after 14 days a pulpectomy was performed on the same primary molars with the two root fillings randomly allocated. The root canal openings were then covered with IRM and the cavity filled with amalgam. After 90 days specimens were harvested and examined under the light microscope with the examiner blind to the treatment. RESULTS:Reaction frequencies in the ZOE-treated versus CH-treated teeth were: no recognisable pulp 89% and 82%, internal root resorption 0% and 1%, external root resorption 11% and 24%, presence of bacteria 5% and 18%, periapical abscesses 24% and 52%. STATISTICS:Fisher's exact probability test showed a statistically significant higher prevalence of periapical abscesses in the CH-treated group (P=0.03, relative risk 2.2). CONCLUSIONS: ZOE pulpectomy is preferred to CH for the treatment of infected pulps in primary molars
  • Thumbnail Image
    Item
    Clinical, histological and microbiological study of hand-excavated carious dentine in extracted permanent teeth
    (2003) Bönecker, M.; Grossman, E.; Cleaton-Jones, P. E.; et al
    Changes in cultivable flora in dentine samples collected before and after hand excavation were examined in association with clinical status of the cavity surface, light microscopy and scanning electron microscopy (SEM). Thirty-five extracted permanent molar teeth with an occlusal caries lesion were excavated with hand instruments according to the atraumatic restorative treatment (ART) approach. Excavation pressure, dentine colour and consistency were recorded at the dentine-enamel junction (DEJ) prior to carious dentine removal and at the cavity floor after the final excavation; a microbiological sample of dentine was taken at both stages. Twelve restored teeth; six with positive and six with negative bacterial growth on the second sample, were selected for light microscopy and SEM. The hand-excavation removed tooth structure was soft, irreversibly damaged, dark and highly infected. Hand excavation reached dentine of increased hardness with a more normal colour to provide a sound structural base for restoration. Light and SEM examination of the cavity floor showed infected dentinal tubules in all 12 teeth examined. Linear logistic analysis showed a statistical association between light-yellow dentine on the cavity floor and an absence of bacterial growth (P = 0.006). This short-term in vitro study showed that caries-producing bacteria remained in dentine close to the cavity floor in 26/35 teeth despite clinical observations that indicated a suitably prepared cavity floor.
  • Thumbnail Image
    Item
    Surface roughness values for resin based materials
    (2004) Grossman, E. S.; Rosen, M; Cleaton-Jones, P.E; et al
    INTRODUCTION: 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.
  • Thumbnail Image
    Item
    Pulpitis induction in baboon primary teeth using carious dentine Streptococcus mutans
    (2004) Cleaton-Jones, P.; Duggal, M.; Parak, R.; et al
    The objective of this equivalency study was to see if a colony of Streptococcus mutans placed into cavities in primary molar teeth produced pulpitis similar to an established pulpitis induction method using carious dentine. In two juvenile baboons (Papio ursinus), occlusal cavities were cut in all 16 primary molar teeth, followed by making a small pulpal exposure after which the cavity was swabbed with 37 per cent phosphoric acid. In one half of the teeth, fresh soft human carious dentine was placed over the pulpal exposure; in the remaining teeth the exposure was covered with a colony of Streptococcus mutans in agar. All the cavities were restored with unlined light-cured composite resin. After 14 days specimens were harvested and examined under the light microscope with the examiner blind to the induction method. In both groups of teeth there was recognisable pulp, hyperaemia, micro-abscesses in the pulp and peri-apical abscesses. Reactions to soft caries were more severe than to Streptococcus mutans. The results show that Streptococcus mutans placed in a cavity with an exposure produces comparable pulpitis to fresh soft human carious dentine in the same type of cavity and that both methods produce pulpitis suitable for testing pulpotomy or pulpectomy treatments.
  • Thumbnail Image
    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 al
    This 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.