Statistical analysis
gingiva, trauma, bleed
SECONDARY, BLEED
Statistical analysis was performed using IBM SPSS version 27 software (IBM Corp., Armonk, NY, USA). Summary descriptive statistics were produced to report demographic features and for each oral health variable.A generalised linear mixed model was used to assess whether there was a difference between the intervention and control groups in terms of all outcomes (OMPI, GI and IBI), over time. A generalised linear mixed model is the ideal statistical model as it allows comparison of groups over time with non-normally distributed data and missing data (An intraclass correlation coefficient (ICC) was generated, using a ‘two-way mixed’ model to assess intra-rater reliability in the measurement of the OMPI. The comparison was made between the clinical score and a repeated measurement calculated from the clinical photographs at a separate time. Reliability testing was not carried out on the GI or IBI because reliability studies for invasive gingival indices have shown that there is a trend for scores to worsen, possibly because the first examination increases the tendency for the gingiva to bleed the second time around (The incidence of trauma secondary to oral hygiene practice, adherence with an oral hygiene regime and satisfaction with an oral hygiene regime were analysed by a comparison of frequency between the two groups.