PubMed Health⌕ Search

Biomedical subjects

P N Galgut

Publications and source records attributed to P N Galgut.

At least 19 recordsLinked to original sources
PubMed2004

A preliminary investigation into the ultrastructure of dental calculus and associated bacteria.

INTRODUCTION: Though dental calculus is generally recognised as comprising mineralised bacteria, areas of non-mineralised bacteria may be present. AIM: To investigate the ultrastructure of non-decalcified young and mature supragingival calculus and subgingival calculus, and the possible presence of internal viable bacteria. MATERIALS AND METHODS: Supragingival calculus was harvested from five patients, 9-10 weeks after scaling and root debridement. Five samples of mature supragingival and subgingival calculus were taken from patients presenting with adult periodontitis. Specimens were fixed and embedded for transmission electron microscopy. RESULTS: The ultrastructure of young and mature supragingival calculus was similar with various large and small crystal types. Non-mineralised channels were observed extending into the calculus, often joining extensive lacunae, both containing intact non-mineralised coccoid and rod-shaped microorganisms. Subgingival calculus possessed more uniform mineralisation without non-mineralised channels and lacunae. CONCLUSION: Supragingival calculus contains non-mineralised areas which contain bacteria and other debris. The viability of the bacteria, and their identification could not be determined in this preliminary investigation. As viable bacteria within these lacunae may provide a source of re-infection, further work needs to be done to identify the bacteria in the lacunae, and to determine their viability.

Adult↗
PubMed2002

Effectiveness of an electrically active brush in the removal of overnight plaque and treatment of gingivitis.

OBJECTIVES: The purpose of the present study was to evaluate the effect of an electrically active toothbrush on established plaque and gingivitis in a 7-month clinical trial. MATERIAL AND METHODS: For this study, 66 volunteers (non-dental University students) were selected on the basis of having moderate gingival inflammation. At baseline, plaque (Quigley & Hein), bleeding upon marginal probing and the Modified Gingival index were assessed on the vestibular, mesio-vestibular, disto-vestibular and lingual surfaces at four sites per tooth. Subjects were randomly divided among two groups; one group brushed with a control brush (Butler GUM 309) while the other used the electrically active test brush. After 2 weeks, 4 weeks, 4 months and 7 months the clinical indices were again recorded. At each assessment the participants received a new brush head for the electrically active brush (test group) or a new manual control toothbrush (control group). RESULTS: All baseline indices appeared to be well balanced. A mean Quigley & Hein plaque score of 1.98 and 2.13 was found in the control and test group, respectively. Little change was observed from baseline to 7 months. The mean bleeding upon marginal probing score at baseline was 0.62 for the control group and 0.59 for the test group. Little to no improvement was observed for the manual brush, whereas an increase in bleeding was observed in the test group in the course of this study. The mean percent reduction in plaque after 1 min of brushing varied throughout the study between 36% and 46%. No difference between the brushes was observed at any time point during the 7-month test period. CONCLUSION: No beneficial effect could be shown for the 'electrically active design feature' compared to a regular manual toothbrush control.

Adolescent↗
PubMed2001

The influence of toothbrush wear on the variables of plaque and gingivitis in clinical trials.

Although toothbrush wear has been shown not to be critical in ensuring optimal plaque removal, the degree of toothbrush wear occurring in a clinical trial may influence the results of the trial. The aim of this study was to determine the effects of toothbrush wear on the clinical variables of dental plaque and gingivitis. There were 107 subjects who participated in this six-month clinical trial in which plaque and gingivitis scores were assessed in relation to toothbrush wear at 2, 4, 12 and 24 weekly intervals. At each appointment, the toothbrushes being used were assessed for wear and replaced if necessary. It was found that 58% of the group were "rapid," and 42% were "slow" wearers. Of the group, 18.6% required replacement toothbrushes within two weeks from baseline with 50.9% of replacement toothbrushes being issued within four weeks of the start of the trial. Two subjects required as many as 10 replacement toothbrushes over the six-month trial period. "Slow" wearers had significantly lower plaque scores than "rapid" wearers at weeks 4 and 12, whereas the "rapid" wearers had significantly lower gingivitis scores than "slow" wearers at weeks 2 and 4. Clinical results show that significant toothbrush wear patterns of individuals participating in clinical trials should be taken into account when designing clinical trials assessing plaque and gingivitis scores. It may be necessary to exclude "rapid" toothbrush wearers from clinical trials that assess plaque and its removal. As the rate of toothbrush wear varied considerably among subjects, the simple classification of subjects into "rapid" and "slow" wearers may require further subgrouping. The surprising result that "rapid" wearers achieved lower levels of gingivitis requires further study to determine if this observation is valid in clinical trials designed for this purpose.

Adult↗
PubMed2001

The relevance of pH to gingivitis and periodontitis.

Although the resting pH of the oral cavity is between 5 and 9, it is also known to vary widely depending on a number of factors. While this phenomenon has been extensively studied in relation to dental caries, little research has been undertaken of its possible significance in relation to gingivitis and periodontitis. This study aimed to investigate any possible correlations between pH and gingivitis and periodontal pocketing. Forty-two subjects with gingivitis and periodontitis were included in this study. Strips of pH indicator paper were placed on the floor of the mouth, soft palate, healthy gingival margins, sites of superficial gingivitis, and in periodontal pockets. It was shown that pH varies in different sites in the mouth. Statistically significant correlations between pH and gingivitis were not identified, but significant correlations between pH and periodontal pocketing were evident, although wide variations were observed between pockets. Randomly distributed pH readings ranging from 2-9 were observed within a single periodontal pocket. This implies that the physiology of processes taking place within periodontal pockets is wide ranging and complex. Different levels of pH indicate different chemical environments which may imply that different disease and reparative processes are occurring simultaneously within each periodontal pocket. The limitations of the assessment technique used in this study were highlighted and compared in relation to results obtained from other studies using more sophisticated techniques and it was found that the results obtained using this unsophisticated technique were in agreement with most of these other studies. Therefore, this technique may have applications in screening for disease activity in clinical practice. However, the need for further work to confirm the observations of this study is necessary to corroborate these associations.

Gingiva↗
PubMed2001

A transmission electron microscopy study of supragingival calculus.

In this study the ultrastructure of human dental calculus was investigated using transmission electron microscopy (TEM). The aim of the study was to observe and clarify the calcification process and the part played by dental plaque in this process. Supragingival calculus from 10 patients was harvested and processed. It was shown that both calculus, and dental plaque within non-mineralised lacunae in calculus, are heterogeneous. Furthermore it was shown that the calculus/dental plaque interface was distinct, although also variable. As calcification occurred apparently independently of dental plaque in some places and when calcification of dental plaque bacteria occurred, it was also varied, it was concluded that supragingival calculus is not simply 'mineralised plaque' but a complex heterogeneous material consisting of numerous phases of mineralisation and non-mineralised areas. The role of dental plaque in the mineralisation process is unclear. However, calculus was not observed arising out of mineralising dental plaque. Mineralising dental calculus and maturing dental plaque are two distinct and different phases occurring simultaneously, albeit with great variability.

Bacteria↗
PubMed2000

Management of data used in clinical trials which is unevenly distributed at baseline.

In this study, 63 healthy adult males were selected for participation in a clinical trial. After initial screening to determine their suitability for participation in the trial, an appointment was scheduled for a professional prophylaxis to derive baseline data and to instruct volunteers in the use of a standard oral hygiene regimen for the trial. Volunteers were then randomly assigned to test and control groups. Follow-up appointments were scheduled two and four weeks thereafter for collection of data. The presence of dental plaque and calculus was assessed at each appointment. Data was to be analysed by using a Student's 't'-test for paired data, but significant differences in the plaque scores were found between the test and control groups at baseline. As a result, the data could not be analysed in this way to obtain a meaningful result. An initial scatter plot of the data revealed six subjects whose plaque scores varied considerably from the group. The aim of this analysis was to evaluate how two different approaches to statistical analysis of data in which significant differences between test and control groups at baseline might affect the inferences drawn from the data. Reasons for significant differences in baseline data in randomly selected groups of volunteers were considered, as well as methods of avoiding this situation. Suggestions on the management of situations in which databases significantly differ include the elimination of 'outliers' and the use of techniques like the Standard Normal Deviate (SND). The data for this study were analysed using these techniques. Although no statistical differences were identified between the two methods of analysis, numerical differences were evident which altered with the type of analysis used. It was concluded that techniques for transformation of the data, like those used in this study, made no difference to the results of subsequent statistical analysis by comparison with the original data set. The influence of sample selection and analysis of data on the results of clinical trials are discussed. The difficulties in interpretation of the results of statistical analyses were highlighted. The influence of imbalances in the data set on the interpretation of the results of statistical analysis was shown to be minimal in this clinical trial.

Adult↗
PubMed1998

Statistical analysis of data derived from clinical variables of plaque and gingivitis.

Selection of suitable subjects and statistical analysis of data derived from clinical trials presents a number of problems. In this trial, clinical data were analysed separately for pooled whole mouth data and for data including positive scores only for the variables of dental plaque and gingivitis. It was demonstrated that comparable data sets and statistical analyses were obtained using both data sets. Furthermore, it was shown that in order to achieve the best possible results in a clinical trial, the variable of gingivitis should be used in preference to plaque scores, that only individuals of high and/or moderate susceptibility to inflammation should be selected for inclusion in the statistical analysis, and that sites which have positive signs of disease only, should be included in the statistical analysis.

Adult↗
PubMed1996

Radiographic evidence of bone regeneration using oxidized cellulose mesh as a bioabsorbable membrane: some case studies.

Guided tissue regeneration has been described as a technique to enhance the regrowth of the periodontal tissues after surgical therapy. Originally, nondegradable materials were used for this purpose, but more recently, degradable materials have been advocated for this purpose. Utilizing an adapted technique in which the material was used as an infill material and barrier membrane, this small study in human subjects has demonstrated radiographically that the defects are filled with a bone-like material over a protracted period. Regeneration of tissues, with bone deposition in infrabony defects, may not be complete as long as 12 months after surgery.

Alveolar Bone Loss↗
PubMed1996

Variations in plaque scores in a small group of individuals over a four week time period.

Individual plaque scores were assessed in a group of individuals over a four week period and compared to the group mean value for the group. No instruction in toothbrushing or professional prophylaxis was undertaken during the period of study. While the mean values for the group remained virtually unchanged throughout the course of the study, the levels of plaque varied considerably between individuals over the period of investigation. Thus it is concluded that the use of plaque scores in clinical practice may not adequately reflect the true relevance of dental plaque and its role in the initiation and progression of gingival inflammation in individuals. Furthermore, pooling of data from clinical trials masks the wide variations and changes in plaque scores in individual subjects which may adversely affect the conclusions drawn from the statistical analysis of the data.

Adult↗
PubMed1996

Supragingival calculus formation in a group of young adults.

The presence of calculus was assessed on the lingual surfaces of the mandibular anterior teeth in a randomly selected group of 63 young adults. The rate of regrowth of calculus after professional prophylaxis was also observed. Twenty-two individuals had supragingival calculus on the mandibular lingual surfaces of their teeth at baseline. Eleven of these individuals demonstrated regrowth of calculus by the end of the study, in spite of repeated professional prophylaxis. Thus, 17.5% of subjects exhibited rapid regrowth of calculus on the mandibular lingual surfaces of their teeth within 2 weeks of professional prophylaxis.

Adult↗
PubMed1995

Observations on the recurrence of destructive periodontal disease during a period of four years after treatment.

The upper and lower extreme percentiles of change in clinical variables were analyzed for a period of four years after completion of periodontal therapy in order to assess the patterns of disease recurrence after treatment. This analysis has demonstrated periods of healing and relapse of sites within individuals, among different individuals, and among different clinical assessment variables utilized. As not all of the sites within different individuals heal or relapse at the same rate, the random asynchronous burst model of pathogenesis seems appropriate to incorporate the different clinical assessment parameters and different sites in different individuals simultaneously. Long-term recession and pocketing, however, may demonstrate opposite trends, giving the erroneous interpretation that attachment levels remain constant with time, whereas, in fact, an active "dynamic equilibrium" of tissue remodeling is established. A statistical model based on the dynamic equilibrium concept would enable account to be taken of the multifactorial interactions that incorporate site and subject interrelationships between different clinical assessment parameters. The dynamic equilibrium model may be suitable therefore as the basis on which statistical analysis of the progression of periodontal disease may be considered. However, as the value of this or other models of the periodontal disease process have not been established, the analysis of data to derive meaningful conclusions from complex statistical techniques may be premature.

Adult↗
PubMed1994

A technique for treatment of extensive periodontal defects: a case study.

This case study describes the use of oxidized cellulose mesh to improve healing of periodontal defects of poor regenerative capacity. Circumferential defects with horizontal bone loss were treated by surgical exposure of the root surface followed by scaling and root planing. Prior to flap replacement, oxidized cellulose mesh was positioned in incremental layers over the defects so as to replace the lost alveolar bone. It was to act also as a barrier to the ingress of epithelial cells and gingival fibroblasts into the healing wound using the principles vof guided tissue regeneration. Healing was good, with minimal post-operative recession. Whether regeneration of alveolar bone and periodontal ligament occurred as a result of using this technique could not be determined in this clinical case study.

Aged↗
PubMed1992

A 4-year controlled clinical study into the use of a ceramic hydroxylapatite implant material for the treatment of periodontal bone defects.

10 patients with chronic adult periodontitis who had greater than 1 tooth with infra-bony pockets were treated at the test defects by periodontal flap procedures with implantation of hydroxylapatite particles; the control defects were treated by the same surgical procedures but without the implant. A total of 58 test defects and 59 control defects were treated. Each defect had measurements carried out at given sites on the involved tooth surfaces, the sites being considered for subsequent tabulation purposes under the category of shallow (less than 3 mm) moderate (3-6 mm) and deep (greater than 6 mm) initial pocket depths. There were 146 and 152 shallow sites, 216 and 241 moderate sites and 140 and 133 deep sites, at test and control sites, respectively. Measurements of recession, probing pocket depths and probing attachment levels were made at 6 months and 1, 2, 3 and 4 years. At all sites over the period of the study, for the moderate and deep initial pockets there was a significant reduction in probing depths and an increase in the probing attachment levels. At the 4th year of assessment for the initially deep pockets, the reduction in probing depths was significantly greater for the sites treated with the implant material. In view of the difficult clinical problem posed by the treatment of teeth with deeper periodontal bone defects, further research using either this type of implant material or similar material should be considered.

Adult↗
PubMed1991

Computerized densitometric analysis of interproximal bone levels in a controlled clinical study into the treatment of periodontal bone defects with ceramic hydroxyapatite implant material.

The aim of this controlled clinical study was to utilize computer-assisted densitometric analysis of radiographs to assess the effectiveness of treating periodontal osseous defects with a sintered hydroxyapatite implant material. It was found that over the 2-year period of the study for the osseous defects treated by the implant material, there was a gain in the height of the hard tissue relative to the cemento-enamel junction; this gain was statistically significant compared with the results for the control sites.

Absorptiometry, Photon↗
PubMed1990

Oxidized cellulose mesh. I. Biodegradable membrane in periodontal surgery.

Regeneration of tissues after surgery has been demonstrated using a variety of membranes placed after surgical exposure of periodontal defects. In this study, biodegradable oxidized cellulose mesh was used in human subjects to improve post-operative healing. Healing was good, with all pockets less than 3 mm post-operatively. Less recession occurred in some of the sites which received the mesh, but this was not significantly different from the sites which did not receive the mesh. A varied healing response was noted in different sites and in different individuals. A number of factors may determine the nature and extent of the healing response, but these are ill defined. Histological investigation of the healing response of the tissues was not possible in this clinical study. The study has shown that oxidized cellulose mesh has the potential to enhance healing after surgery, and it may be useful as an alternative biodegradable material for use in the technique of guided tissue regeneration.

Aged↗
PubMed1990

Oxidized cellulose mesh. II. Using hydroxy-apatite bone grafting material in the treatment of infrabony defects.

Biodegradable oxidized cellulose mesh has been used in conjunction with hydroxyapatite synthetic bone grafting material to enhance retention of the graft material and to improve post-operative healing of infrabony defects treated surgically. Initially a good healing response was achieved, but there was a tendency for the sites to relapse in the 8 wk following surgery. A tendency to relapse in reconstructive dentistry is well known, and the possible factors which limit the amount of regeneration of tissues are considered. Although there appear to be limitations on the regeneration possible in tissues, the factors that determine these limitations are poorly understood at present.

Alveolar Bone Loss↗