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Biomedical subjects

W P Holbrook

Publications and source records attributed to W P Holbrook.

At least 19 recordsLinked to original sources
PubMed2005

Profile and competences for the European dentist.

This paper presents the profile and competences for the European Dentist as approved by the General Assembly of the Association for Dental Education in Europe at its annual meeting held in Cardiff in September 2004. A task-force drafted the document, which was then sent to all European Dental Schools. Reactions received were used to amend the document. European dental schools are expected to adhere to the profile and the 17 major competences but the supporting competences may vary in detail between schools. The document will be reviewed in 5 years time. This paper will be disseminated to ministries of health, national dental associations and dental specialty associations or societies in Europe and these organisations will be asked to offer their comments. This information will be used in the reviewing process to be started in 2007. It is hoped that the availability of this document will assist dental schools in Europe to further harmonize and improve the quality of their curricula.

Dentistry↗
PubMed2005

Enamel opacities in 8-year-old Icelandic children in relation to their medical history as infants.

OBJECTIVES: Opacities in tooth enamel were found in 34% of 8-year-old Icelandic children in 1970. This study aimed to measure the current prevalence of non-fluorotic enamel opacities in the maxillary incisors and to determine if their occurrence was related to significant events in the medical history. DESIGN: The prevalence of demarcated enamel opacities was recorded photographically by calibrated examiners. SETTING: Subjects lived in Reykjavík, Iceland. SAMPLE AND METHODS: A random sample of 290 children aged eight years was examined in 1997-8. Parents were asked if the child had a history of (i) colic as an infant and/or (ii) repeated middle-ear infection. RESULTS: Demarcated white enamel lesions, not resembling fluorosis, were seen in 41% of children (teeth photographed wet) rising to 51% (teeth photographed dry). Enamel hypoplasia was seen in 11% of wet teeth and 15% of dry teeth. Parents of 94/288 children (32.6%) reported that their child had infant colic and 52/94 (55.3%) had received medication. Three episodes or more of middle-ear infections per year were reported for 123/290 (42.4%) children. Significant association was seen between the presence of demarcated enamel opacities and a history of otitis media. Diffuse enamel opacities, assumed to be fluorosis, were not associated with events reported from the medical history. CONCLUSIONS: Non-fluoride opacities of teeth are still prevalent in Icelandic children especially those with a history of infections in infancy. Without a careful diagnosis these opacities might be confused with fluorosis.

Cariostatic Agents↗
PubMed2004

Relationship between dental erosion, soft drink consumption, and gastroesophageal reflux among Icelanders.

The aim of this study was to determine the prevalence of dental erosion in young Icelandic adults (19-22 years old) and patients with gastroesophageal reflux disease (GERD), in relation to their soft drink consumption and gastroesophageal reflux. Eighty subjects (40 males and 40 females), comprising 57 young adults (mean age 21 +/- 2 years) and 23 GERD patients (mean age 35 +/- 10 years), were enrolled in this study. All subjects answered a detailed frequency questionnaire of soft drink consumption and participated in a clinical examination. Erosion was scored for incisor and molar teeth separately. No significant difference was observed in the prevalence of dental erosion between young adults and GERD patients. However, by combining the two study groups a three-fold higher risk of having erosion in molars or incisors was found for subjects drinking Coca-Cola three times a week or more often ( p < 0.05). Additionally, significantly higher erosion scores were found in molars among subjects drinking more than 1 litre of carbonated drinks (all brands) per week ( p < 0.05). It is concluded that the frequency of soft drink consumption is a strong risk factor in the development of dental erosion.

Adult↗
PubMed2004

Clonal persistence of oral Fusobacterium nucleatum in infancy.

Once established, early-colonizing bacterial species tend to persist in the mouth. To obtain detailed information on the population dynamics of early-colonizing oral anaerobes, we examined the clonal diversity and persistence of clones among oral Fusobacterium nucleatum populations during the first 2 yrs of life. Consecutive salivary samples from 12 infants, collected at 2, 6, 12, 18, and 24 mos of age, yielded a total of 546 F. nucleatum isolates for clonal typing with arbitrarily primed PCR (AP-PCR). Up to 7 AP-PCR types were simultaneously detected in each sample. In 11 out of the 12 infants examined, AP-PCR types persisted for up to 1 yr. Strain turnover rate was high during the first year of life, but then the occurrence of persistent clones increased. This study indicates a wide genetic diversity within the species and provides evidence for the increasing persistence of F. nucleatum clones in the oral cavity with age.

Chi-Square Distribution↗
PubMed2001

Herpetic gingivostomatitis in otherwise healthy adolescents and young adults.

The purpose of this study was to review and analyze the records of herpes simplex infections from a specialist Oral Medicine clinic in Iceland, to investigate the clinical impression that the age of patients experiencing initial infection with this virus was higher than expected and that the character of the clinical picture of the disease had changed. Records of patients with herpes infections attending the Oral Medicine clinic covering a 3-year period were examined and the clinical and virological data analyzed. Diagnosis was based on clinical appearance, history, and viral identification with culture or detection of viral DNA by means of the polymerase chain reaction. Records of 60 patients (34 female) were included in the study (mean age, 23.1 years; range, 2 68 years). No patients were known or suspected to be positive for human immunodeficiency virus, none was known to be immunocompromised, and 38 patients (mean age, 16.6 years; 21 female) were diagnosed as having primary herpetic gingivostomatitis. Eighteen patients (mean age, 36.2 years; 11 female) had lesions of recurrent herpes simplex infection present on the oral mucosa. Primary infection with herpes simplex virus was more common in young adults than had been expected. Recurrent infections appeared on the oral mucosal even in otherwise healthy patients, and the clinical course of these infections in this age group sometimes followed a more severe course than that seen in young children.

Adolescent↗
PubMed1999

Identifying clinically important gram-negative anaerobes from the oral cavity.

Gram-negative oral anaerobes have frequently been associated with periodontal disease, some species more frequently than others. The confusing classification of these organisms has often obscured the association with disease of particular species within this group of organisms. This investigation aimed to compare different identification methods that could be applied in clinical research. Clinical isolates were collected and identified by three different methods: screening with phenotypic tests, commercial identification kits, and a 16S rRNA-based polymerase chain reaction (PCR) method. Forty-three reference strains of 19 Prevotella and Porphyromonas species were also included in the investigation. The phenotypic screen easily differentiated Porph. gingivalis from the other pigmented species. The screen also gave a good indication of separation of the lactose-fermenting species from the lactose non-fermenting species, although diversity can be seen in beta-galactosidase activity. Commercial identification kits did not add much to identification achieved with the phenotypic screen, only 20% of Porph. gingivalis isolates could be identified to species level with the kits. Neither the kits nor the phenotypic screen could differentiate Pr. intermedia and Pr. nigrescens. With the PCR method, Pr. intermedia and Pr. nigrescens were easily separated, and Porph. gingivalis was readily identified. Because of 16S rRNA gene sequence similarity, Pr. melaninogenica and Pr. veroralis could not be separated by the PCR method.

Bacterial Typing Techniques↗
PubMed1998

Aqueous hydrocortisone mouthwash solution: clinical evaluation.

Patients often experience difficulties in applying topical steroids in orabase to the oral mucosa, particularly when large areas need to be covered. An aqueous hydrocortisone mouthwash solution has been developed, one that was anticipated to be more acceptable to patients. The solution contains hydrocortisone (0.3% w/v) in a 4.5% (w/v) 2-hydroxypropyl-beta-cyclodextrin solution. Hydroxypropylmethylcellulose (0.5% w/v) was used to increase the viscosity of the solution and to promote the hydrocortisonecyclodextrin complex. One hundred and two patients with aphthous ulceration, lichen planus, and other mucosal conditions used the mouthwash in an open clinical efficacy study. Most patients reported some or considerable improvement following a 2-week course of treatment with the mouthwash: 26 of 33 (78.8%) patients with aphthous ulceration were 'much better', as were 26 of 54 (48.1%) patients with lichen planus and 5 of 16 (31.3%) patients with other mucosal lesions. No serious side effects were reported. Aqueous mouthwash solutions offer a potential vehicle for topical steroid therapy of oral mucosal lesions.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMed1998

A hemagglutinating variant of Prevotella melaninogenica isolated from the oral cavity.

Strains resembling Prevotella melaninogenica were isolated from healthy subjects and patients with periodontal disease and were identified using: a 5-test phenotypic screen; commercial identification kits; and a 16S rRNA-based polymerase chain reaction (PCR) method. Eleven clinical isolates closely resembling P. melaninogenica, and all from patients with periodontitis, were able to agglutinate erythrocytes. In the electron microscope, hemagglutinating isolates showed fimbria-like structures, that were not seen on non-hemagglutinating isolates. Some strains were further classified with PCR-restriction fragment-length polymorphism (RFLP) of 16S rRNA genes. Amplified 16S rDNA was digested using five different endonucleases, separated with agarose gel electrophoresis, stained and photographed. Photographs were then scanned, digitized and a distance matrix calculated using Dice coefficient, where the presence or absence of a band was used as a character. The distance matrix was plotted as a phenogram. At 70% similarity six clusters were seen. Type strains of separate Prevotella species did not fall into any cluster. Hemagglutinating isolates fell into three clusters: four clustered with the type strains of P. melaninogenica and Prevotella veroralis; four with other P. melaninogenica isolates and two hemagglutinating isolates clustered together Prevotella loescheii. The PCR-RFLP results showed that the hemagglutinating strains did not form a homogenous group inside the Prevotella genus.

Adult↗
PubMed1998

Approximal caries and sugar consumption in Icelandic teenagers.

The aim of this study, conducted in 1994, was to examine the association between approximal caries and sugar consumption in teenagers residing in three fluoride-deficient areas in Iceland while controlling for a number of behavioral, residential and microbiological factors. One hundred and fifty subjects (mean age 14 years) selected from the Icelandic Nutritional Survey (INS) were examined radiographically and they completed questionnaires about sugar consumption frequency. Total grams of sugar intake were obtained from the INS for each subject. Caries experience on approximal surfaces, diagnosed from radiographs, was used as the dependent variable in the analyses. Altogether 45.2% of subjects were caries free on approximal surfaces. The overall sample was found to have a mean DFS on approximal surfaces of 2.73 (s=4.36) per subject. Average daily total sugar intake was 170 g per subject and the mean number of sugar-eating occasions between meals was 5.32 (s=6.29) per subject. The regression model indicated that the frequency of between-meal sugar consumption was associated with approximal caries, with frequency of candy consumption being the most important of the sugar variables. In multivariate analysis, no relationship was found between dental caries and total daily intake of sugar, although a significant relationship between total sugar consumption and presence of caries was seen in bivariate analysis. Between-meal consumption of sugar remains a risk factor for the occurrence of dental caries, especially in populations with moderate-to-high levels of dental caries experience.

Adolescent↗
PubMed1997

Trends in dental health among Icelandic urban children.

Caries experience, oral hygiene and caries-related salivary parameters were recorded in a 20% representative sample of 12-year-old schoolchildren in Reykjavik, Iceland in 1991. The majority of the children was re-examined 3 years later in 1994. Trends in prevalence of caries and salivary bacteria were assessed by comparison with an analogous earlier longitudinal study (1984-87). Mean DFS values for 12-year-olds were 12.1 and 4.1, for 15-year-olds 23.3 and 11.3 in the earlier and later study, respectively. Reduction in DFS was 66% and 52% for the respective age groups. The decline was most pronounced in the group with low caries prevalence. Trends in caries experience were paralleled by salivary bacteria. The mean caries scores and frequency distributions of 15-year-olds in 1994 closely resembled those of 12-year-olds a decade earlier, suggesting a delay rather than a true fall in caries prevalence.

Adolescent↗
PubMed1996

Putative periodontal pathogens, antibody titres and avidities to them in a longitudinal study of patients with resistant periodontitis.

OBJECTIVE: To study changes in antibody titres and antibody avidities to putative periodontal pathogens in patients with resistant periodontitis and to compare these findings with the result of culture of these pathogens. SUBJECTS AND METHODS: Patients meeting strict clinical criteria in whom periodontal therapy had failed to prevent disease progression were studied microbiologically and immunologically over a 75-week period. Particular reference was made to the isolation of Actinobacillus actinomycetemcomitans (Aa) and Porphyromonas gingivalis (Pg) together with changes in antibody titres and avidities to these organisms between baseline examination and week 75. RESULTS: Pg was eliminated following antibiotic treatment but metronidazole and amoxycillin therapy failed to remove Aa in all cases. Antibody avidities to these pathogens were higher in patients than in matched controls but no change in avidity was noted during the course of treatment. Most antibody titres were not significantly higher in patients than in controls. CONCLUSIONS: Continued disease progression characterised these patients who, nevertheless, mounted an immune response to the periodontal pathogens but this appeared to be inadequate to stop the disease.

Adult↗
PubMed1995

Tooth erosion, gastroesophageal reflux, and salivary buffer capacity.

To obtain information on the connection between tooth erosion and acid gastroesophageal reflux, 14 patients (mean age, 15.7 years) with tooth erosion were investigated with simultaneous 24-hour pH monitoring in the esophagus and the oral cavity. Salivary parameters were also investigated in a larger group of 62 erosion patients (mean age, 21 years) and compared with a group of 50 controls (mean age, 28 years). No changes in oral pH were observed in a total of 339 acid reflux episodes, not even in long supine reflux episodes. Extended periods of lowered intra-oral pH to the level of 4 to 5 were observed but not connected with gastroesophageal reflux episodes. Significantly more (p < 0.001) erosion patients (34 of 62) had low salivary buffer capacity compared with controls (10 of 50).

Adolescent↗
PubMed1995

Mutans streptococci, lactobacilli and caries experience in 12-year-old Icelandic urban children, 1984 and 1991.

In order to evaluate changes in salivary counts of cariogenic bacteria and relate these to trends in caries experience, stimulated saliva was collected from a 20% random sample of 12-yr-old residents of Reykjavik, Iceland (252 children) in 1991 under conditions consistent with those of a survey conducted in 1984. The mean and median counts of salivary mutans streptococci and lactobacilli remained similar in the two studies. However, the frequency distribution at lower levels of mutans streptococci differed significantly between 1991 and 1984, e.g. in the present study 25.8% of the children had < 10(5) compared with 13.8% in the study 1984. The mean caries prevalence in the permanent dentition (DFStot) was 11.0, which is significantly lower than in 1984 (mean DFStot 28.8). A significant difference in caries prevalence was found at various levels of salivary mutans streptococci. Strep. mutans (serotype c/e/f) was carried by all mutans streptococci-positive children, save one child, who carried only Strep. sobrinus. The proportion of 12-yr-olds who carried Strep. sobrinus had decreased significantly to 15.7% from 34.0% in 1984. Significantly more children with Strep. sobrinus showed high levels of total mutans streptococci than children with only Strep. mutans. As the case was in 1984 significantly more Strep. sobrinus carriers had a high level of salivary lactobacilli as well as higher caries prevalence than the children who did not carry this species.

Child↗
PubMed1995

Longitudinal study of caries, cariogenic bacteria and diet in children just before and after starting school.

Fifty 5-yr-old preschool children living in Akranes, a small community in West Iceland known to have a high caries prevalence, were investigated with respect to caries, salivary counts of mutans streptococci and lactobacilli, and consumption of cariogenic foods. Fifteen months later, after being in school for half a year, 43 of the 50 children were reexamined and investigated as before. Mean dmfs scores rose from 7.1 to 9.0, but the scores including initial caries rose from 9.7 to 15.3. Mutans streptococci were carried by 84% of children on both occasions with a mean count 2.1 and 3.6 x 10(5) cfu/ml. Lactobacillus carriage increased from 29 to 38% and the mean count from 5.1 to 13 x 10(3) cfu/ml at 6 yr. The frequency of consumption of sugar-containing foods increased from 4.2 to 5.2 intakes per day and between-meal snacks rose from 3.0 to 3.7 per day. Children classified as "misusing" sugar were 59% at 5 yr and 83% at 6 yr. The mean caries score at 6 yr for children "misusing" sugar was 10.7 but only 2.0 for those not misusing sugar. Thus the deterioration in dental health appears, in these children, to be associated with the increased consumption of sweets and other cariogenic between-meal snacks after starting school.

Child↗
PubMed1995

Cariogenic bacteria in a longitudinal study of approximal caries.

Two hundred and seventeen approximal spaces, initially caries free, in 58 patients were studied clinically and radiographically, at intervals of 6 months, for 3 years. Samples of approximal dental plaque were removed for culture of Streptococcus mutans, Streptococcus sobrinus, and lactobacilli. During the study approximal caries developed in 16 subjects (27.6%) at 30 sites (13.8%), involving 42 teeth. 56 of 58 (96.7%) subjects harboured S. mutans at some time during the study, 62.1% lactobacilli, and 29.3% had S. sobrinus. The counts of S. mutans were significantly higher in those subjects that also carried S. sobrinus than in the remaining subjects. A persisting high count of S. mutans > 10(5) colony-forming units per millilitre (CFU/ml) or a count that rose by > or = 1 x log10 CFU/ml during the study was seen in 25 of 30 sites that subsequently became carious (p < 0.001). Similarly, counts of lactobacilli that were consistently > 10(3) CFU/ml or rising by > or = 1 x log10 CFU/ml were seen in 17 of 30 sites that became carious (p < 0.001). Although there were strong statistical associations between approximal caries and high or rising counts of these cariogenic bacteria, the bacterial counts were not good predictors of future approximal caries at that particular site.

Adolescent↗
PubMed1994

Evaluating surgical, non-surgical therapy in periodontic patients.

Eleven highly susceptible periodontitis patients volunteered for a one-year prospective study of surgical and non-surgical periodontal therapy. The patients had high oral hygiene standards and had not received antimicrobial therapy within six months. This study suggests that both types of therapy are equally effective in treating recurrent lesions.

Adult↗
PubMed1993

Prediction of dental caries in pre-school children.

Data obtained in a longitudinal study of caries incidence and caries-related factors were analysed with a view to producing a model for the prediction of caries. In direct correlations, caries incidence was significantly associated with bacterial, dietary and salivary variables; but when the data were examined by stepwise regression the strongest variables were the baseline caries score and misuse of sugar. Counts of Streptococcus mutans entered into the analysis but only as a relatively minor component. Similar significant relationships were seen with the determination of odds ratios. A caries activity test was formulated combining the following caries-associated variables: high counts of S. mutans, or lactobacilli, or the misuse of sugar, or frequent consumption of paediatric medicines. Regular use of fluoride tablets could compensate for paediatric medicine use or misuse of sugar. Such a caries activity test if it had been applied to the children at baseline would have had a positive predictive value of 0.76, a negative predictive value of 0.82, a sensitivity of 0.8 and a specificity of 0.78. Combining tests made the prediction of caries more accurate and in the population for which it was intended gave a reliable means of detecting those children most in need of enhanced caries prevention.

Child↗