Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.797067
Title: Evaluation of adjunctive and alternative techniques in periodontal therapy
Author: Radvar, Mehrdad
Awarding Body: University of Glasgow
Current Institution: University of Glasgow
Date of Award: 1995
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Abstract:
Mechanical debridement of supragingival but predominantly subgingival bacterial plaque and calculus has been the mainstay of traditional treatment for periodontal disease. Practical difficulties and occasionally lack of response or recurrence of disease in some patients have made investigators search for more effective alternative or adjunctive methods of therapy. In this thesis, two modern approaches, local antimicrobial delivery systems, as adjuncts to scaling and root planing, and the Nd:YAG laser, as an alternative to scaling and root planing, were investigated. The study designed to investigate subgingival antimicrobial systems was of randomised parallel design and sought to evaluate the efficacy of 3 locally delivered antimicrobial systems as adjuncts to scaling and root planing in the treatment of sites with persistent periodontal lesions. Fifty-four patients with 4 pockets > 5 mm and bleeding on probing (BOP) and/or suppuration were randomised in 4 treatment groups including: scaling and root planing either alone (S) or plus application of 25% tetracycline fibre (S&T) or 2% minocycline gel (S&Mi) or 25% metronidazole gel (SScMe) . All treatments resulted in significant improvement in pocket depth (PD), attachment level (AL) , BOP and the Modified Gingival Index (MGI) scores which were maintained until the end of the 6-month follow-up period, although some rebound towards baseline occurred in all groups at the 6-month visit. The improvements in clinical parameters were greater in the S&T group than other groups at any time point. At the 6- week visit, the pocket depth reduction (APD) was significantly greater in the S&T group than in the S group (p=0.002). There was no significant difference between groups in APD at 3 and 6-month visits. The difference between groups in improvement of AL (AAL) or BOP was not significant at any time point. The frequency of sites with suppuration reached zero only in the S&T group at the 6-week and 3-month visits. No serious adverse effects were observed or reported in any of the treatment groups. The S&T was the most time-consuming treatment. While all 3 locally applied antimicrobial systems appear to offer some benefit over scaling and root planing alone, S&T treatment demonstrated the greatest advantage in the treatment of persistent periodontal lesions, particularly at suppurating sites. A further aim of the study was to evaluate the effect of smoking on the outcome of periodontal therapy. Regardless of the type of treatment, APD and AAL were consistently greater in non-smoker subjects than smokers. The General Linear Model analysis was used for APD and AAL to take into account, variations in the treatments, number of smokers per group and baseline pocket depth. There was consistently a significant interaction between the 'smoking' and the 'baseline PD'. Further analysis using linear regression indicated that while there was a significant relationship between the baseline PD and the APD or AAL among the non-smokers, a weak and insignificant relationship existed among the smoker subjects. These results strongly suggest that smoking is a factor to consider in the determination of prognosis of periodontal treatment, particularly in deep pockets. The aim of the first laser study was to evaluate the effects of Nd:YAG laser treatment on sub-gingival calculus, cementum and dentine, in vitro at different power settings and durations. Eight different laser treatment settings were tested on subgingival calculus, cementum and dentine specimens and were assessed using scanning electron microscopy (SEM). Micrographs were taken from each treated site at x100 and x750 magnifications. An arbitrary scale (from 0 to 3) was used to score the degree of damage caused by the laser. Generally, the laser caused greater damage on calculus than either cementum or dentine specimens, although in cases of complete ablation of calculus, the underlying cementum was ablated too. This may limit selective calculus removal without damaging the underlying dental tissues. Three-way analysis of variance showed that for calculus, the power setting, pulse repetition, and the duration of exposure, contributed independently to the mean damage score in an additive way. The results also showed that there was variability in susceptibility of different teeth and different parts of each tooth, which was true for calculus, cementum and dentine. This variability may preclude the safe and predictable removal of calculus by specific laser settings.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.797067  DOI: Not available
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