The Effects of Chlorhexidine/Thymol Varnish on the Abutment Teeth in Partial Denture Wearers.

• 2 baseline samples of the Gingival Crevicular Fluid (GCF) and the subgingival samples. The first baseline sample will be done on the day of the first impressions and the second one the day of denture fitting.
• The following information will be recorded on the CRFs: Silness and Löe Plaque index, BoP, probing depth, clinical attachment level, LoA, Kennedy classification, material of the partial denture and type of clasp (or no clasp) and ICDAS code.
• The patient will also fill in the OHIP-14 questionnaire (Oral Health Impact Profile) to assess their self perception of oral health.
• A photograph of the abutment teeth and the partial denture will be taken.
• We will also take a full history of the patient including: name, DOB and medications.
• The GCF and subgingival sampled will be taken every 6 months on the appointment where the varnish is applied.
• All the laboratory samples will be labelles with the same identification number that the patient has been allocated and a date will also be written on it. All the samples will be analysed in Plymouth and stored in a - 50°C freezer (the samples taken at the University of Aberdeen will be stored in the same type of freezer and shipped periodically to the Penninsula University for tests maintaining the same temperature conditions). They will be testing the microbial composition and GCF cytokine profile of the sub gingival environment
• All measurements will be reassessed at 12 months and 24 months. In addition to the denture hygiene index: Budtz-Jørgensen (1977) Index (plaque accumulation on the denture).

The data will be collected by one clinician in each dental school. All clinicians will be calibrated appropriately.

Calibration: Before any examination starts we will assess the consistency of each examiner (intra-exmainer) and also the variation between exmainers (inter-exmainer reproducibility). Each examiner will independently examiner the same group of 20 subjects and compare his or her findings. When findings contain major discrepancies, subjects should be recalled in order that differences in diagnoses can be reviewed by the exmainers and resolved by group discussion. If certain examiners consistently produce significantly different results from the majority, and attmepts to correct their performance fail, they will be excluded from the team. It will be made clear to all potential examiners, before these exmainations begin, that ability to standardize examination results is not a measure of clinical skills (Oral Health Surveys 4th edition. WHO. Geneva 1997) All the data will be recorded on the case report forms (CRFs).