PubMed Health⌕ Search

Biomedical subjects

P E Murray

Publications and source records attributed to P E Murray.

At least 19 recordsLinked to original sources
PubMed2006

Oral health in Florida nursing homes.

OBJECTIVES: The purpose of this study was to measure the oral health and hygiene status among 265 South Florida nursing home residents aged between 45 and 98 years. METHODS: The oral health and hygiene status of the residents were assessed by noting the presence of calculus, caries, gingivitis, cheilitis, apthous ulcer, dry mouth and red or white lesions. RESULTS: The incidence of nursing home residents with calculus was 79.6% and the remaining 20.4% were edentulous. More than half of residents had oral problems (50.6%) the commonest was gingivitis (36.6%), followed by caries (26%) and tooth fracture (15.9%). Almost half the residents wore dentures (47.2%). Statistical analysis was conducted using analysis of variance (P-values). Ageing of the residents was statistically correlated to a worsening of oral hygiene status (P<0.0066), absence and presence of one or two dentures (P<0.0034) and a loss of teeth (P<0.0001). CONCLUSIONS: The ageing of residents is correlated to increasing oral health problems and the loss of teeth. Oral health neglect affects almost all of the nursing home residents. Care providers should receive education and training from dental hygienists to improve the standard of oral hygiene and health of the elderly.

Age Distribution↗
PubMed2003

Odontoblast morphology and dental repair.

OBJECTIVES: To investigate the changes in morphology and activity of pulp odontoblasts in response to cavity restoration variables and patient factors. METHODS: Class V non exposed cavities were prepared in the intact 1st or 2nd premolar teeth of 27 patients, aged between 9 and 17 years-old. Following tooth extraction, the area of reactionary dentine and the area of the odontoblasts were measured using computerised histomorphometry. RESULTS: The cytoplasm to nucleus ratio of the odontoblasts was found to increase beneath cut dentinal tubules, following the secretion of reactionary dentine. However, none of the patient or preparation variables were found to be correlated with changes in the odontoblast cytoplasm to nucleus ratio. CONCLUSIONS: Morphological changes in human odontoblasts is directly related to their capacity to repair dentine injuries and provide pulp protection. Changes in odontoblast morphology reflect secretory activity.

Adolescent↗
PubMed2003

Remaining dentine thickness and human pulp responses.

AIM: To evaluate pulp responses as a function of remaining dentine thickness (RDT) of 98 class V cavity preparations in 49 teeth of 31 patients aged 10-16 years. METHODOLOGY: Shallow cavities were restored with amalgam, deeper cavities or pulp exposures were restored with amalgam lined with calcium hydroxide or with zinc oxide eugenol. Teeth were extracted after 3-89 days for orthodontic reasons. Following processing for light microscope analysis, the number of odontoblasts, pulp inflammation, and repair was recorded. RESULTS: In comparison with independent odontoblasts, the numbers of odontoblasts were reduced by 13.6% beneath a RDT of 2.5-0.5 mm, 33.7% beneath a RDT of 0.5-0.01 mm and 99.0% beneath pulp-exposed cavities. Reparative dentine was observed following pulp exposure and reactionary dentine was observed with a mean RDT of 0.77 mm (2.5-0.01 mm). Reactionary dentine secretion was influenced by RDT and restorative materials. Pulp inflammation was not influenced by RDT in the present study. CONCLUSIONS: Cavity RDT mediates a powerful influence on underlying pulp tissue vitality but it has little effect on reactionary dentine secretion and inflammatory activity. Gross tissue injury explains the poor pulp capping prognosis following exposure and underlies the need to avoid this type of injury. Following restoration, a RDT of 0.5 mm or greater is necessary to avoid evidence of pulp injury.

Adolescent↗
PubMed2003

Histomorphometric analysis of odontoblast-like cell numbers and dentine bridge secretory activity following pulp exposure.

AIM: The purpose of this study was to collect quantitative information about the numbers and dentine bridge secretory activity of odontoblast-like cells following dental pulp exposure. METHODOLOGY: The numbers and secretory activity of odontoblast-like cells were measured histomorphometrically between 7 days and 2 years in 161 pulp-exposed nonhuman primate teeth. The area of dentine bridges and the dimensions of cavity preparations were measured. The density of odontoblast-like cells and subjacent reorganizing tissue cells were measured beneath dentine bridge formation. The presence of operative dentine debris and tunnel defects in bridges was noted. Pulp inflammation was categorized according to ISO standards. Bacteria were detected using McKay's stain. RESULTS: The area of dentine bridges was mediated by the density and secretory activity of odontoblast-like cells over time. The cell density of subjacent reorganizing tissue was found to be strongly associated with that of odontoblast-like cells. Bacterial microleakage was found to impede dentine bridge secretion by odontoblast-like cells. CONCLUSIONS: Pulp reparative activity occurs naturally beneath capping materials in the absence of bacterial microleakage. The outcome of pulp-capping treatments could be beneficially influenced by concentrating attention on limiting the width of pulp exposure, minimizing pulp injury by limiting the creation of operative debris and placing materials which prevent bacterial microleakage.

Analysis of Variance↗
PubMed2002

Analysis of incisor pulp cell populations in Wistar rats of different ages.

Pulp cell function and viability is important for maintaining tooth vitality throughout life. However, the effects of ageing on pulpal cell populations and pulp tissue remodelling are still unclear. The aim here was to quantify age-related cell-density changes in the pulp of rat incisor teeth, using histomorphometric analysis and ANOVA. Mandibular (n=35) and maxillary (n=34) incisors were carefully extracted from 20 Wistar rats aged between 1 and 18 months, fixed and processed for light microscopy. Cell counts were performed in mature and immature regions at both labial and lingual aspects of all teeth. Odontoblast and subodontoblast cell densities were reported per mm of pulp-dentine border and core fibroblast density per mm2 pulp tissue. Irrespective of age, odontoblast and subodontoblast densities were lower in the immature than the mature regions of both maxillary and mandibular incisors (P<0.001). However, in both regions odontoblast and subodontoblast densities decreased significantly with increasing age (P<0.0001). The age-related reduction in odontoblasts was significantly greater in mature than immature regions (P<0.02) but not influenced by other variables. In contrast, the age-related reduction in subodontoblasts was significantly different between mandibular and maxillary teeth (P=0.012) but not influenced by site. Unlike odontoblasts and subodontoblasts, core fibroblasts showed small but significant increases with increasing age (P<0.0001). These age-related reductions in the density of odontoblasts and subodontoblasts may partly explain the slower rate of secondary dentine secretion and decreased pulp repair activity associated with ageing.

Aging↗
PubMed2001

The effect of cavity restoration variables on odontoblast cell numbers and dental repair.

OBJECTIVES: Dentinal repair following cavity restoration is dependent on several parameters including the numbers of surviving odontoblasts. The purpose of this study was to examine the effects of cavity cutting and restoration treatments on post-operative odontoblast numbers. METHODS: 353 Standardised non-exposed rectangular Class V cavities, were cut into the buccal dentin of intact 1st or 2nd premolar teeth of 165 patients, aged between nine and 25 years of age. Composite cavity restorations with various etching treatments were compared with resin-modified glass ionomer cements, enamel bonding resins, as well as polycarboxylate, calcium hydroxide, and zinc oxide eugenol materials. Following tooth extraction (20-381 days) for orthodontic reasons, the area of the reactionary dentine and the area of the odontoblasts was measured histomorphometrically. RESULTS: Odontoblast numbers and dentine repair activity were found to be influenced more by cavity restoration variables, than the choice of cavity filling materials or patient factors. The most important cavity preparation variable was the cavity remaining dentine thickness (RDT); below 0.25mm the numbers of odontoblasts decreased by 23%, and minimal reactionary dentine repair was observed. CONCLUSIONS: Odontoblast injury increased as the cavity RDT decreased. In rank order of maintaining odontoblast numbers beneath restored cavities with a RDT below 0.5mm, and using calcium hydroxide for comparison; calcium hydroxide (100%), polycarboxylate (82.4%), zinc oxide eugenol (81.3%), composite (75.5%), enamel bonding resin (49.5%) and RMGIC (42.8%). The vitality and dentine repair capacity of the pulp is dependent on odontoblast survival. Variations in the extent of odontoblast injury caused during operative procedures, may be the major underlying reason for the success or failure of restorative treatments.

Adolescent↗
PubMed2001

Transdentinal stimulation of reactionary dentinogenesis in ferrets by dentine matrix components.

OBJECTIVES: Trans-dentinal stimulation of reactionary dentinogenesis may be mediated through cellular signalling by bio-active components released from the dentine matrix during injury. Understanding of these processes will be important to guide dentinal repair activity following restorative surgery. The purpose of this study was to investigate the effects of implanting isolated dentine matrix proteins within cavity preparations on dentinal repair activity and odontoblast survival using a controlled experimental animal model. METHODS: Forty-five ferret canine teeth each had a standardised non-exposed cylindrical Class V cavity cut into the buccal dentine. Ten cavities were restored with zinc oxide eugenol, as a control. Two different lyophilised preparations of dentine matrix components were implanted on the axial floor of the remaining 35 cavities prior to filling with zinc oxide eugenol. After post-operative periods of 2, 7, 14, 28, and 90 days, the teeth were extracted and examined histomorphometrically and the data analysed statistically by analysis of variance tests. RESULTS: The odontoblasts beneath the restored cavities responded to the presence of the two dentine matrix preparations by increasing the mean area of reactionary dentine secreted by 433 and 578%, and the numbers of odontoblasts remained stable. CONCLUSION: Dentine matrix components can stimulate reactionary dentinogenesis in non-exposed cavity preparations. It will now be important to identify how this may be harnessed as a part of routine restorative surgery to optimise treatment outcomes with a biological basis.

Analysis of Variance↗
PubMed2001

Trans-dentinal stimulation of tertiary dentinogenesis.

Trans-dentinal stimulation of tertiary dentinogenesis has long been recognized, and has traditionally been ascribed to diffusion of irritant substances arising during injury and restorative treatment. Identification of bio-active components, especially growth factors including TGF-beta s, sequestered within dentin matrix provides a new explanation for cellular signaling during tertiary dentinogenesis. Both isolated dentin matrix components and pure growth factors (TGF-beta s) have been shown to signal cellular events leading to reactionary and reparative tertiary dentinogenesis. Release of these bio-active components from dentin matrix may arise during carious attack and other injury to the tissue, and also during subsequent surgical intervention and restoration of the tooth. Both cavity-conditioning agents and leaching from restorative materials may contribute to release of these components. Distance of diffusion, as determined by cavity residual dentin thickness, and other restorative parameters may influence the signaling process after release of these components. Careful consideration of the interplay between tissue injury and surgical and restorative material factors is required for optimum exploitation of the exquisite regenerative capacity of dentin-pulp for more biological approaches to clinical treatment of dental disease.

Animals↗
PubMed2001

Restorative pulpal and repair responses.

BACKGROUND: Each year, about 90 million new restorations are placed in the United States and 200 million are replaced. Controversy surrounds the pulpal reactions and frequency of bacterial microleakage associated with common restorative materials. The authors investigated and compared pulpal reactions to different types of restorative materials. METHODS: Two hundred seventy-two teeth with standardized rectangular Class V unexposed cavities were restored with resin-based composite bonded to dentin; resin-based composite bonded to enamel; resin-modified glass ionomers, or RMGI; amalgam lined with zinc polycarboxylate, or ZnPC; amalgam lined with calcium hydroxide, or Ca(OH)2; or zinc oxide-eugenol, or ZnOE. Teeth were extracted for orthodontic reasons between 20 and 381 days later. The authors categorized pulpal responses according to standards set by the Federation Dentaire Internationale and the International Organization for Standardization. Bacteria were detected using Brown-Brenn-stained sections. Pulpal responses were evaluated using histomorphometric analysis and analysis of variance statistics. RESULTS: The results showed that RMGI was the best material for preventing bacterial microleakage, and resin-based composite bonded to enamel was the worst. In regard to minimizing pulpal inflammatory activity, ZnOE was the best material and resin-based composite bonded to enamel was the worst. In terms of maximizing odontoblast survival beneath deep cavity preparations, Ca(OH)2, was the best material and RMGI was the worst. CONCLUSIONS: The results show that bacterial microleakage, pulpal injury and repair responses varied widely with different restorative materials. CLINICAL IMPLICATIONS: The authors recommend that RMGI be used to restore teeth with cavities that are shallow to moderate in depth, with the floor of deep cavities being lined with Ca(OH)2 before the teeth are restored with RMGI.

Adolescent↗
PubMed2000

Tooth slice organ culture for cytotoxicity assessment of dental materials.

The purpose of this work was to develop a tooth slice organ culture method to assess the response of the cells of the dental pulp to commonly used dental materials and products. Wistar rat tooth slices were grown in culture for two and ten days in the presence of dental materials. After culture, the tooth tissues were processed and the responses of the pulpal cells were analysed histomorphometrically. Cytotoxic cell destruction was observed following the direct application of test materials to tooth slices (n = 298) after 10 days in culture (MANOVA, P = 0.0001), whilst the restoration of prepared deep dentine cavities (n = 30), with test products, did not result in a significant amount of pulpal injury (MANOVA, P = 0.287). In rank order of causing pulpal injury, the test materials from the most to the least cell destructive, was; Salicylic acid. Calcium hydroxide, Kalzinol zinc oxide eugenol, high-mercury Amalgam, Prime & Bond, Dycal, Barium sulphate, Hypocal, Scotchbond, Calasept, Life and One-step. Tooth slice organ culture, provided a cytotoxicity screening method for dental materials, bearing a closer physiological resemblance to the clinical situation than cell culture screening methods. Tooth slice culturing may have the potential to replace some types of in vivo animal experimentation, as there is a clear need to reduce this form of testing.

Animals↗
PubMed2000

Human odontoblast cell numbers after dental injury.

OBJECTIVES: The purpose of this study was to measure the changes in odontoblast cell numbers in response to cavity restoration variables and patient factors, and the effect these factors have on dental repair by tertiary dentinogenesis. The number of vital odontoblasts is a critical factor for pulpal repair following restorative surgery, and yet little information is available on these cell numbers. METHODS: Class V non-exposed cavities were prepared in the buccal surface of intact first or second premolar teeth of 27 patients, between 9 and 17 years of age. Following tooth extraction (28-163 days) the area of reactionary dentine and the area of the odontoblasts were measured histomorphometrically. RESULTS: Patient factors, as well as cavity preparation and restoration variables, had little effect on the numbers of odontoblasts per pulpal unit area. However, the age of the patient did appear to have an effect on the reactionary dentine secretory capacity of odontoblasts per unit area, and on the relative number of odontoblasts beneath cut dentinal tubules. CONCLUSIONS: Odontoblast cell numbers were maintained following the preparation of cavities cut into dentine with a 0.5mm residual dentine thickness. The repair capacity of the pulp-dentine complex would appear to be age dependent, this may explain differences in the success of various restorative treatments between patients.

Adolescent↗
PubMed2000

Ultrastructural localisation of TGF-beta exposure in dentine by chemical treatment.

Transforming growth factor-beta (TGF-beta) sequestered in dentine matrix has an important role in dental tissue repair after injury and its exposure at sites of injury may stimulate tertiary dentinogenesis. This study aimed to investigate the expression of TGF-beta isoforms in mature human dentine matrix and the ability of chemical treatments to expose TGF-beta on the cut surface of dentine using gold immunolabelling and subsequent scanning electron microscopy examination. TGF-beta1 was the only isoform that could be detected in human dentine and the nature of the chemical treatment of the tissue influenced its detection. EDTA treatment provided good exposure of TGF-beta1 on the dentine surface, whilst citric acid and sodium hypochlorite treatments revealed lesser amounts of this isoform. Only minimal staining for TGF-beta1 was observed in samples treated with phosphate-buffered saline. TGF-beta2 and -beta3 could not be detected in the specimens with any of the treatments. This study suggests that TGF-beta1 is the only TGF-beta isoform expressed by human odontoblasts to be sequestered in dentine implying that differences in isoform-extracellular matrix interactions may exist. Information on chemical treatment of tissue specimens for immunostaining may provide a useful basis for selection of tissue preparation techniques for clinical restorative treatment procedures to facilitate TGF-beta mediated reparative processes at sites of dental injury.

Citric Acid↗
PubMed2000

The influence of sample dimensions on hydroxyl ion release from calcium hydroxide products.

The purpose of this study was to compare the rate of hydroxyl ion release from commercially available setting and non-setting calcium hydroxide products. The rate of hydroxyl ion release is important, as this has been suggested to be the main factor in the therapeutic activity of these products. In total, hydroxyl ion release was measured from 1104 samples of Dycal, Life, Calasept and Hypocal in solution using in vitro titration. The rate of hydroxyl ion release was measured for up to 14 days, using two sizes of sample surface area. The dimensions of the exposed sample surface area was found to be an important physical constraint to the hydroxyl ion release from non-setting calcium hydroxide products, whereas this was not found to be the case with setting products. The range in hydroxide activity between products was found to be 298%. In rank order of hydroxide ion release, from the most to the least active was: Hypocal, Calasept, Life and Dycal. The differences in the rate of hydroxyl ion release from these products may have some implications for their clinical applications. It is suggested that in cases where the oral healing responses have been poorer than expected, the size and seal of prepared cavities could have negatively influenced the therapeutic release of hydroxyl ions from non-setting calcium hydroxide products.

Analysis of Variance↗
PubMed2000

Postoperative pulpal and repair responses.

BACKGROUND: Each year in the United States, the success of 10 million surgically restored carious lesions depends on a favorable tertiary dentin repair response to preparation, restoration and patient factor variables. The authors investigated the relationship between these variables and dentinal response. METHODS: Standardized rectangular Class V restoration preparations were cut into the buccal dentin of intact first or second premolars of 27 patients without exposing the pulp and were restored. The patients were between 9 and 17 years of age. The treated teeth were scheduled for extraction for orthodontic reasons. After tooth extraction, the tertiary dentin was analyzed histomorphometrically. RESULTS: The area of tertiary reactionary dentin was found to be correlated using linear regression analysis of variance with restoration residual dentin thickness (P = .0024), age of the patient (P = .0045), restoration floor surface area (P = .0266) and restoration width (P = .0415). The authors did not find a correlation with the premolar position (P = .0594), sex of the patient (P = .650), pulpal inflammatory reaction (P = .613) or the time elapsed since surgery (P = .531). Restoration with zinc oxide eugenol was found to negatively influence tertiary dentin matrix secretion (post hoc analysis of variance, P = .030). CONCLUSIONS: The age of a patient at treatment, the choice of restorative material and the size of the restoration preparation are all factors that can positively or negatively affect the pulpal repair response. CLINICAL IMPLICATIONS: Age of the patient affects dentin repair capacity and may be a factor in treatment planning decisions. Minimizing the cutting of dentin, especially the width and base of the preparation, reduces the probability of recurrent pulpal complications.

Adolescent↗
PubMed1999

The rôle of thymidine phosphorylase/PD-ECGF in cancer chemotherapy: a chemical perspective.

The angiogenic growth factor thymidine phosphorylase/PD-ECGF has been identified as a potential target in the development of anti-cancer drugs. This review firstly discusses the biological rôle of TP/PD-ECGF and its importance in the activation of 5-fluorouracil and its prodrugs. The chemistry and chemotherapeutic potential of TP/PD-ECGF inhibitors are also discussed.

Animals↗
PubMed1988

Evaluation of antacid tablets and liquid in fasting and fed men and women.

In view of in vitro tests suggesting good performance of an experimental tablet formulation of an aluminum hydroxide-magnesium hydroxide antacid, a study was conducted to evaluate the efficacy in vivo. Twenty-three healthy men and women were enrolled in the study, which was carried out in two parts: fasting and postprandial. Eight of the volunteers failed to qualify because of repeated baseline pH greater than 2.5. In the 15 participants who qualified, the intragastric pH was monitored for up to 240 minutes after the administration of one or two experimental tablets, 5 or 10 ml of a commercially available liquid antacid, or placebo. In the fasting subjects (n = 10), the antacids rapidly increased the mean pH. One antacid tablet and 5 ml of liquid antacid yielded similar results, with mean peak pH values of 5.2 and 4.8 and durations above pH 3.5 of 25 and 40 minutes, respectively. When the doses were doubled, 10 ml of liquid produced a peak pH of 6.7 and maintained the pH above 3.5 for 40 minutes, whereas two tablets produced a peak pH of 4.8 and maintained pH above 3.5 for 15 minutes. In the fed subjects (n = 10), neither antacid formulation at either dose significantly raised intragastric pH. Further studies are needed to establish the optimal time for postprandial administration of antacids.

Adult↗
PubMedDate not supplied

Comparison of pulp responses following restoration of exposed and non-exposed cavities.

OBJECTIVES: The purpose of this study is to compare and contrast differences of pulp responses between non-exposed and exposed cavity preparations in terms of inflammation, frequency of bacterial microleakage, odontoblast and odontoblastoid cell numbers, and tertiary dentine formation. METHODS: Class V non-exposed cavities (n=161) and exposed cavities (n=161 teeth) were prepared in non-human primate teeth. Cavities were restored with calcium hydroxide [Ca(OH)(2)], resin modified glass ionomer, or resin composite. Following extraction (7-730 days), bacteria were detected with McKays stain and pulp reactions were categorized according to ISO guidelines. Teeth were analyzed histomorphometrically and statistically using analysis of variance tests. RESULTS: Exposed cavities in comparison with non-exposed cavities were found to have more severe inflammation (p=0.0001), greater quantities of tertiary dentine (p=0.0001), and an increased frequency of bacterial microleakage (p=0.0034). The density of odontoblastoid cells beneath pulp exposed tertiary dentine was found to be 47.8% of odontoblast cell density beneath non-exposed dentine (p=0.0001). CONCLUSIONS: The restoration of exposed cavity preparations is associated with more traumatic pulp injury and repair responses. Consequently, efforts should be made to minimize iatrogenic dentine removal during cavity preparation and the creation of pulp exposures whenever possible.

Analysis of Variance↗