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Biomedical subjects

A Rawlinson

Publications and source records attributed to A Rawlinson.

At least 19 recordsLinked to original sources
PubMed2006

A digital SLR or intra-oral camera: preference for acquisition within an image analysis system for measurement of disclosed dental plaque area within clinical trials.

OBJECTIVES: The aim of this investigation was to compare the accuracy and reproducibility of images acquired from two types of camera (digital SLR camera, Kodak DCS410, KJP, UK and an intra-oral camera, Schick Technologies, UK) for application within an imaging system used for the quantification of disclosed dental plaque. METHODS: Subjects refrained from brushing their teeth for 24 h. Their teeth were then disclosed with Erythrosin FDC Red 3 and duplicate sets of images were obtained by each examiner of the upper central and lateral incisors. Images were then saved and measured for dental plaque area. These data were used to calculate reliability. RESULTS: No statistically significant bias in the measurements of plaque area was found. The reliability results showed the method was reliable. However, the image analysis system incorporating the 35 mm SRL camera was more reliable for both operators, as demonstrated by their intra-operator results. This was also collaborated by the inter-operator results. CONCLUSION: In this investigation the digital SLR camera combined with the image analysis system and frame permitted greater reliability of dental plaque surface area measurements than the digital intra-oral camera. This conclusion was derived both from the reliability data and from the perceived ease of use and flexibility of both camera types. When combined with the use of the custom-made frame, the images using the digital SLR camera were highly reproducible, confirming the systems application within clinical trials.

Adult↗
PubMed2005

An in-vitro and in-vivo methodology study of alveolar bone measurement using extra-oral radiographic alignment apparatus, Image Pro-Plus software and a subtraction programme.

OBJECTIVES: (a) To validate a method for acquiring reproducible radiographic images and repeatable measurements of digital images. (b) To investigate the clinical and radiographic changes following periodontal surgery and in a periodontally healthy control group. METHODS: In-vitro study. Sixteen dried human skulls had replicate intra-oral radiographs taken using an extra-oral alignment apparatus under simulated clinical conditions, and measurements were made on the images using Image Pro-Plus analysis software. In-vivo study. Seven subjects, aged 38-63 years with chronic periodontitis, were treated using replaced flap surgery. Nine patients with healthy periodontal tissues were recruited as a control group. Clinical measurements and radiographs were taken pre-surgery and 6 months afterwards, and at the same interval for untreated healthy controls using the alignment apparatus. Radiographs were analysed using Image Pro-Plus and subtraction radiography. RESULTS: Radiographs had a high degree of reliability (ICC 0.98-0.99) for the in-vitro study and intra-operator repeatability of measurements was high (ICC 0.65-0.99) for the in-vivo study. Over this interval there were both significant clinical improvements and in bone gain within infra-bony defects on radiographs. Subtracted images showed that out of 17 surgically treated sites, 13 showed evidence of bone gain, one showed no change, two showed bone loss and one could not be interpreted due to poor alignment. Overall there were no significant clinical or radiographic changes in the control group. CONCLUSIONS: Radiographic images were highly reproducible. Measurements had a high degree of repeatability. The methods used allowed accurate quantitative and qualitative measurement of change in alveolar bone. This technique would allow accurate measurement of any changes in alveolar bone levels in patients with periodontal disease.

Adult↗
PubMed2004

Quantification of dental plaque on lingual tooth surfaces using image analysis: reliability and validation.

AIM: The aim of this study was to increase the versatility and further validate the method reported by Smith et al. (2001) by testing the reliability of plaque measurement against two well-known dental plaque quantification methodologies using image analysis in a clinical trial. METHOD: The teeth of 40 subjects were disclosed before digital images of the labial and lingual surfaces of their upper and lower incisors were acquired. The amount of plaque present was quantified using a modification of the method described by Smith et al. (2001). The method was modified for obtaining images of the lingual surfaces by incorporating the use of orthodontic occlusal mirrors and 5-mm pieces of moistened blue articulating paper used to enable calibration. Plaque measurements were made from 320 upper and lower anterior teeth from the 40 subjects by two operators. Fliess' coefficient of reliability was used to assess intra- and inter-operator reliability and the independent sample t test was used to assess statistical significance between test and control groups after checking the data for normality. For validation, measurements were recorded using the Turesky et al. (1970) (modification of the Quigley & Hein (1962) plaque index and the Addy et al. (1983) plaque area index. The results were compared with the image analysis method using Pearson's correlation coefficient. RESULTS: The results for reliability were within Fliess' range of "excellent" for both intra-operator repeatability and inter-operator reproducibility. Pearson's correlation coefficients showed highly significant values indicating the close similarity between all three methods. CONCLUSIONS: This method for the measurement of dental plaque on lingual surfaces of anterior teeth proved reliable. The combined results from the labial and lingual surfaces of anterior teeth using image analysis produced trial conclusions comparable with the alternate plaque quantification methods used, with less clinician time and further producing a permanent database of images for future use.

Adult↗
PubMed2003

Activation of human matrix metalloproteinase 2 by gingival crevicular fluid and Porphyromonas gingivalis.

AIM: To assess the potential of gingival crevicular fluid (GCF) from adult periodontitis patients and Porphyromonas gingivalis proteases to activate matrix metalloproteinase 2 (MMP-2) in vitro. MATERIAL AND METHODS: GCF samples were collected from each of 15 adult periodontitis patients, from a clinically healthy site, a deep (>6 mm) bleeding site, and a deep nonbleeding site. The GCF samples were examined for general proteolytic activity, gelatinolytic activity and ability to activate pro-MMP-2 by zymography. Ultrasonic extracts of a range of clinical isolates of P. gingivalis cells and purified arg- and lys-gingipains were also assessed for their ability to activate pro-MMP-2. RESULTS: GCF from deep nonbleeding sites showed higher general proteolytic activity than samples from deep bleeding and healthy sites but this did not reach statistical significance. Pefabloc, a general serine protease inhibitor, inhibited the majority (92%) of the proteolytic activity. GCF samples contained neutrophil MMP-9 in its latent form in 93% of the samples, and in its activated form in 40% of the samples. In contrast, MMP-2 was present in only trace amounts in 9% of the samples. When latent MMP-2 was added to these GCF samples, it was converted to the activated form (59 kDa) in 68% of the samples. Lower molecular weight (55 and 45 kDa) activated forms also appeared in 53% of the samples, particularly those from deep sites. Activation to the 55 and 45 kDa forms was inhibited by MSAAPket (a neutrophil elastase inhibitor), whereas Pefabloc completely inhibited the activation of latent MMP-2. All ultrasonic extracts of P. gingivalis activated latent MMP-2 in a concentration- and time-dependent manner. Also, latent MMP-2 was activated by purified arg-gingipain but less efficiently by lys-gingipain. CONCLUSION: These findings suggest that P. gingivalis arg-gingipain and neutrophil elastase present in GCF can activate latent MMP-2, which may contribute in vivo to local periodontal tissue destruction.

Adhesins, Bacterial↗
PubMed2001

Effect of non-surgical periodontal treatment on clinical parameters and the numbers of Porphyromonas gingivalis, Prevotella intermedia and Actinobacillus actinomycetemcomitans at adult periodontitis sites.

BACKGROUND, AIMS: The purpose of this study was to relate the numbers of Porphyromonas gingivalis, Prevotella intermedia and Actinobacillus actinomycetemcomitans cells to clinical parameters at diseased and healthy periodontal sites before and after non-surgical periodontal therapy using a sensitive quantitative PCR method (Q-PCR). METHOD: The sensitivity of the Q-PCR was less than 10 cells for all three species. Subgingival plaque samples were collected from 541 sites in 50 adult periodontitis subjects pre-treatment, post-treatment and at a follow-up visit (3-6 months post-treatment). Pocket probing depth, attachment loss and bleeding on probing were recorded at each visit and both healthy and diseased sites in each subject were sampled. RESULTS: Quantification revealed that P. gingivalis counts were associated with pocket depth (p=0.006) and attachment loss (p=0.010); however, neither P. intermedia nor A. actinomycetemcomitans was associated with the clinical signs examined. Post-treatment, there was a significant decrease in the numbers of all three species in both the diseased and healthy sites (86-99%) but none were eradicated. Positive associations were found between any two of the three species studied both pre- and post-therapy. By the follow-up visit, there was a significant improvement in the probing depth of deep sites (p=0.001) but in no other clinical parameters. CONCLUSION: This study demonstrates the usefulness of Q-PCR for enumerating putative pathogens in clinical periodontal specimens and that the numbers of the three organisms in all sites decrease with non-surgical periodontal therapy.

Adult↗
PubMed2000

Interleukin-1 and IL-1 receptor antagonist in gingival crevicular fluid.

BACKGROUND/AIMS: This study aimed to investigate the cytokine IL-1beta and its receptor antagonist IL-1ra in gingival crevicular fluid (GCF), in patients with adult periodontitis. METHOD: A total of 40 GCF samples were harvested from 10 subjects with moderate to severe adult periodontitis and 10 healthy controls. Subjects were selected from both genders, with all the upper anterior teeth present, and with no relevant systemic illness, pregnancy or recent medication. All subjects were non-smokers and had not received any periodontal therapy within the preceding 3 months. Deep bleeding sites, deep non-bleeding sites and healthy sites were investigated in relation to upper anterior teeth. Clinical measurements were recorded for each site, after obtaining a GCF sample. IL-1beta and IL-1ra were quantified using new commercially available ELISA kits (Quantikine), and could be detected in all samples. RESULTS: The mean concentration for IL-1beta was 0.11 (SD 0.14) pg/microl for bleeding periodontitis sites, 0.04 (0.05) pg/microl for non-bleeding periodontitis sites, and 0.01 (0.03) pg/microl for healthy sites (p<0.001). In contrast, the mean concentration for IL-1ra was 6.99 (9.78) pg/microl for healthy sites, 0.59 (0.44) pg/microl for non-bleeding periodontitis sites, and 0.44 (0.36) pg/microl for bleeding periodontitis sites (p<0.001, except for comparisons between bleeding and non-bleeding periodontitis sites, p>0.05). For healthy sites, a strong inverse relationship was found between IL-1beta and IL-1ra levels in GCE. CONCLUSIONS: The results suggest a strong relationship between the severity of adult periodontitis and the increasing GCF levels of IL-1beta and decreasing levels of IL-1ra.

Adult↗
PubMed2000

A novel closed-tube quantitative--PCR method for enumerating Porphyromonas gingivitis, Prevotella intermedia and Actinobacillus actinomycetemcomitans.

Enumeration of specific periodontopathogens in subgingival plaque samples has been problematic because of either lack of sensitivity, specificity or the time taken to identify the organisms. These problems can be overcome using PCR, but quantification by this technique is more difficult. We report a simple quantitative PCR method developed for enumerating Porphyromonas gingivalis, Prevotella intermedia and Actinobacillus actinomycetemcomitans in clinical samples. The method relies upon inclusion of ethidium bromide in a closed-tube PCR reaction and measurement of resultant amplicons by quantifying the fluorescence generated when UV-light is passed through the walls of the amplification tube. Hence, both PCR and detection are performed in the same tube. The technique was compared with a quantitative competitive PCR and a commercial colorimetric quantitative PCR and proved to be at least as sensitive, specific and reliable for enumeration of the target bacteria. However, its speed and convenience make it particularly useful for large-scale analyses in both clinical laboratories and epidemiological studies.

Aggregatibacter actinomycetemcomitans↗
PubMed2000

Enumeration of Porphyromonas gingivalis, Prevotella intermedia and Actinobacillus actinomycetemcomitans in subgingival plaque samples by a quantitative-competitive PCR method.

Porphyromonas gingivalis, Prevotella intermedia and Actinobacillus actinomycetemcomitans are believed to play an important role in adult periodontitis, but the significance of their relative numbers and progress of the disease is still unclear. Traditional quantitative methods are generally time-consuming and inaccurate. The aim of this study was to develop a sensitive, quantitative PCR technique that would be useful for enumerating P. gingivalis, Pr. intermedia and A. actinomycetemcomitans in subgingival plaque samples from subjects with adult periodontitis. Primers to the following genes were employed: the fimbrial gene (fimA) of P. gingivalis, the 16S rRNA gene of Pr. intermedia and the leukotoxin-A (lktA) gene of A. actinomycetemcomitans. Competitive templates were constructed either by sequence deletion between primer binding sites or by annealing of the primer binding sites to an appropriate DNA core so as to yield products of a different size from that obtained with the target template. Coamplification of target and competitive templates yielded products of expected size and non-specific recognition by the primers was not found. The sensitivity of the designed primers was 100 cells of P. gingivalis, 100 cells of Pr. intermedia and 10 cells of A. actinomycetemcomitans. The three species were found in subgingival plaque samples collected from both healthy and diseased sites by the quantitative-competitive (QC)-PCR method and the technique was more sensitive than cultural methods. For determining the proportions of each of the three periodontopathogens, the total number of bacteria in the samples was enumerated by quantitative-PCR with 16S rRNA universal primers (27f and 342r). The findings indicate that QC-PCR is a useful method for enumerating bacteria in clinical oral specimens and the technique could play a role in the investigation of disease progression.

Actinobacillus Infections↗
PubMed1999

Periodontal probing depth and subgingival temperature in smokers and non-smokers.

The aim of this study was to investigate the difference in subgingival temperature between smokers and non-smokers at different probing depths, and the effect of probing depth on subgingival temperature for smokers and non-smokers. 20 smokers and 20 non-smokers, with adult periodontitis, and retained upper anterior teeth were included. Initially sublingual temperatures were recorded, followed by subgingival temperature, pocket probing depth, and bleeding upon probing measurements at 3 buccal points at probing depths of 2, 3, 4, 5, and 6 mm for each of the anterior teeth. Sublingual temperatures were consistently higher than subgingival temperatures. The subgingival temperature measurements of pockets which bled upon probing, were subtracted from the sublingual temperature to produce temperature differentials (delta T), independent of individual body temperature, that were compared between smokers and non-smokers. The relationship between probing depth and delta T was examined in, and between, smokers and non-smokers for bleeding sites. delta T was found to decrease linearly with the increase of probing depth, suggesting a subsequent increase of subgingival temperature. Smokers were found to have significantly increased delta T(suggesting lower subgingival temperatures) compared to non-smokers, at probing depths of 2, 3, 4, and 5 mm. The differences in delta T for sites 6 mm in depth were not statistically significant between the 2 groups. It is concluded that for maxillary buccal anterior sites, there is a decrease of temperature differentials with an increase of probing depth at bleeding sites for both smokers and non-smokers. Smokers had higher temperature differentials compared to non-smokers, at probing depths of 2, 3, 4 and 5 mm.

Adult↗
PubMed1999

An in-vitro evaluation of a dental subtraction radiography system using bone chips on dried human mandibles.

The aim of this in vitro study was to evaluate the ability of digital subtraction radiography to detect small differences in bone density between 2 dental images captured with the Digora radiographic imaging system. 5 dried human mandibles were held in a fixed position and cortical bone chips were superimposed on the alveolar bone between the 1st molar and 2nd premolar teeth. For each mandible, a reference image was obtained without bone chip placement. Subsequently, another image without a bone chip and a series of 10 images with bone chips ranging from 1.2 to 35.3 mg, were recorded. Each of the initial images of the 5 mandibles was then compared to the 11 subsequent images using digital subtraction radiography. The difference in density between the 2 images, at the site between the 1st molar and 2nd premolar, was calculated and represented as a volume equivalent of aluminium. Regression analysis demonstrated a close relationship between the weight of the bone chips and the aluminium equivalent density difference between the 2 radiographs (r2 = 0.96). Good results were obtained with the smaller bone chips that more closely resembled the dimensions of bone changes likely to be of clinical interest (1-8 mg). It is concluded that this subtraction radiography system is suitable for clinical investigations of localised small changes in alveolar bone and for the diagnosis and monitoring of destructive forms of periodontal diseases.

Absorptiometry, Photon↗
PubMed1999

Gingival crevicular fluid osteocalcin in adult periodontitis.

This study aimed to detect the levels of osteocalcin in gingival crevicular fluid (GCF) from healthy (< or =3 mm sulcus depth and non-bleeding) and diseased sites (> or =6 mm probing depth and bleeding) in subjects with adult periodontitis, in order to further investigate its potential as a possible marker of the disease process. Periodontal probing depths, attachment levels and gingival indices were recorded from one healthy and one diseased site in each of 20 subjects with adult periodontitis. Both GCF accumulated in the periodontal pocket or sulci and GCF flowing into the periodontal pocket or sulci over a three-minute interval were sampled. The amounts of osteocalcin in each GCF sample was determined using immunoassays. A mean of 2.34 ng/site (2.7 microg/ml) osteocalcin was found at diseased sites and a mean of 2.47 ng/site (5.47 microg/ml) was found at healthy sites for the accumulated GCF collection method. A mean of 0.17 ng/ site (2.17 microg/ml) osteocalcin was found at diseased sites and a mean of 0.14 ng/ site (1.85 microg/ml) at healthy sites for the flow method of GCF collection. There were no statistically significant differences between osteocalcin levels in diseased and healthy sites in subjects with adult periodontitis.

Adult↗
PubMed1998

Subdural haemorrhages in infants: population based study.

OBJECTIVES: To identify the incidence, clinical outcome, and associated factors of subdural haemorrhage in children under 2 years of age, and to determine how such cases were investigated and how many were due to child abuse. DESIGN: Population based case series. SETTING: South Wales and south west England. SUBJECTS: Children under 2 years of age who had a subdural haemorrhage. We excluded neonates who developed subdural haemorrhage during their stay on a neonatal unit and infants who developed a subdural haemorrhage after infection or neurosurgical intervention. MAIN OUTCOME MEASURES: Incidence and clinical outcome of subdural haemorrhage in infants, the number of cases caused by child abuse, the investigations such children received, and associated risk factors. RESULTS: Thirty three children (23 boys and 10 girls) were haemorrhage. The incidence was 12.8/100 000 children/year (95% confidence interval 5.4 to 20.2). Twenty eight cases (85%) were under 1 year of age. The incidence of subdural haemorrhage in children under 1 year of age was 21.0/100 000 children/year and was therefore higher than in the older children. The clinical outcome was poor: nine infants died and 15 had profound disability. Only 22 infants had the basic investigations of a full blood count, coagulation screen, computed tomography or magnetic resonance imaging, skeletal survey or bone scan, and ophthalmological examination. In retrospect, 27 cases (82%) were highly suggestive of abuse. CONCLUSION: Subdural haemorrhage is common in infancy and carries a poor prognosis; three quarters of such infants die or have profound disability. Most cases are due to child abuse, but in a few the cause is unknown. Some children with subdural haemorrhage do not undergo appropriate investigations. We believe the clinical investigation of such children should include a full multidisciplinary social assessment, an ophthalmic examination, a skeletal survey supplemented with a bone scan or a skeletal survey repeated at around 10 days, a coagulation screen, and computed tomography or magentic resonance imaging. Previous physical abuse in an infant is a significant risk factor for subdural haemorrhage and must be taken seriously by child protection agencies.

Child Abuse↗
PubMed1998

Phylloquinone in gingival crevicular fluid in adult periodontitis.

Phylloquinone is a lipid soluble vitamin which is an absolute growth requirement for black-pigmented anaerobes, many of which are implicated in the aetiology of periodontal diseases. This cross-sectional study aimed to detect the levels of phylloquinone in GCF from healthy and diseased sites in subjects with adult periodontitis, in order to investigate further its potential role in the disease process. The sample consisted of eighteen patients with adult periodontitis. Periodontal probing depths, attachment levels and gingival indices were recorded from one healthy and one diseased site in each subject. GCF was sampled and the amount of phylloquinone in each sample was determined using reverse-phase high performance liquid chromatography coupled to electrochemical detection. The mean amount of phylloquinone in accumulated GCF from diseased sites was 406 pg/site and 80 pg/site from healthy sites (p=0.013). When the amounts of phylloquinone in GCF were expressed as concentrations the values were 228 ng/ml and 3350 ng/ml for diseased and healthy sites respectively (p=0.084). These findings suggest the levels of phylloquinone in GCF differs in periodontal health and disease in subjects with adult periodontitis. The total phylloquinone at diseased sites may provide the nutritional requirements favouring the growth of black-pigmented anaerobes.

Adult↗
PubMed1998

The effect of cleaning on blood contamination in the dental surgery following periodontal procedures.

Blood contamination of 16 surfaces in the dental surgery was investigated using the Kastle-Meyer test for haemoglobin, after three types of periodontal procedures had been performed on a total of 30 patients. The effect of cleaning surfaces contaminated by blood was investigated using the same test. Cleaning materials used in the dental surgery were tested to rule out the possibility of false positive outcomes and the sensitivity of the test was determined prior to the study. The results show a marked variation in the degree of contamination and efficacy of cleaning following treatment. Overall, root planing was associated with the most widespread and frequent blood contamination and gingival surgery the least. The surgery work surface, edge of the spittoon, aspirator tube and ultrasonic scaler handpiece into which the ultrasonic insert fits, were the most frequently contaminated surfaces. The work surface, dentist's pen, light switch and handle were cleaned most effectively. The least effectively cleaned surfaces were the water dispenser switch, aspirator tube, bracket table and ultrasonic scaler handpiece. Methods for reducing this potential source of cross-infection are discussed.

Blood↗
PubMed1997

Subgingival temperature in smokers and non-smokers with periodontal disease.

The purpose of this study was to compare subgingival temperature in a group of smokers to that of a group of non-smokers with similar levels of periodontal disease. 40 adult subjects, 20 cigarette smokers and 20 non-smokers with evidence of adult periodontitis were examined. Subgingival temperature was measured at 6 sites around each of 4 maxillary anterior teeth. Probing depth, and the presence or absence of bleeding was also recorded. In addition, the sublingual temperature was recorded. All sites were classified as diseased or healthy. Healthy sites did not bleed and had a probing depth of < or = 4 mm, diseased sites were any site which had a probing depth > or = 5 mm, or which bled on probing. Mean sublingual and site temperatures were calculated for smokers and non-smokers. Mean temperature differentials (delta T) between the sublingual temperature and the site temperature were calculated for each site. Smokers had a warmer mean sublingual temperature than non-smokers. A significant difference in subgingival site temperature was demonstrated between the smokers and non-smokers, with the mean site temperature being 0.4 degree C warmer in smokers (p < 0.01). When healthy or diseased sites were compared between smokers and non-smokers, smokers also had warmer mean site temperatures than non-smokers for both healthy and diseased sites (p < 0.01). When the mean temperature differentials (delta T) between healthy and diseased sites were compared across each group, significant differences were also found. For healthy sites, the smokers had a mean delta T 0.2 degree C lower (p < 0.01) than the non-smokers, representing warmer sites. In diseased sites however, delta T was 0.3 degree C higher (p < 0.01) in smokers, representing cooler sites.

Adult↗
PubMed1995

Effects of surgical treatment on the microbial flora in residual periodontal pockets.

The aim of this study was to investigate the effects of modified Widman flap surgery on the microbial flora in deep residual periodontal pockets remaining after non-surgical treatment. Micro-organisms from samples of subgingival plaque obtained from adult periodontitis sites in six patients were cultured aerobically and anaerobically, on a variety of media and identified. Non-surgical treatment produced little clinical improvement and had little effect on the total microbial count. Subsequent modified Widman flap surgery resulted in significant clinical improvements which were accompanied by an overall reduction in microbial counts. Regular reviews for scaling and oral hygiene maintained the clinical improvements and balance in favour of beneficial microbial species during the 1 year of the study.

Adult↗
PubMed1993

Rationale and techniques of non-surgical pocket management in periodontal therapy.

Traditional views on pocket instrumentation in periodontal therapy have centred upon the thorough scaling and planing of root surfaces, which aim to remove all calculus and substantial amounts of 'necrotic' and 'contaminated' cementum. The lack of scientific evidence for removing calculus in periodontal therapy, was highlighted by Frandsen and recent studies have also questioned the need for extensive root planing to remove 'substantial' amounts of cementum. The need for some degree of pocket instrumentation during periodontal therapy however, is beyond doubt, as clinical studies on the efficacy of nonsurgical periodontal treatment published during the last decade have clearly shown. A review of this important topic is therefore timely and this paper aims to elucidate some of the concepts which are currently the subject of debate. A resume of the formation and characteristics of the subgingival environment is a necessary starting point.

Dental Cementum↗