For caries prevention, a 0.2% sodium fluoride mouth rinse is typically recommended for use once weekly. This regimen provides sufficient fluoride exposure to strengthen tooth enamel without causing adverse effects.

The correct concentration for topically applied acidulated phosphate fluoride is 1.23% (Answer: 2). This concentration is commonly used in various dental products like gels, foams, and varnishes for professional in-office applications to strengthen tooth enamel and prevent decay. It is acidulated to facilitate better penetration into the enamel.

Custom-formed mouth protectors are made from impressions of the patient’s teeth and offer the best fit and protection. They are typically made by a dental professional and are more comfortable than stock or boil-and-bite mouthguards. While plastic molded and stock mouthguards are also available, custom-formed ones are considered superior in terms of protection and compliance.

A higher drop-out rate can reduce the power of a study, as it leads to a smaller sample size and potentially less reliable results. To maintain the statistical significance and power of the study, a larger sample size must be enrolled initially to account for the expected number of participants who will not complete the study. Other factors that influence sample size include the incidence of the disease, the significance level, and the size of the expected treatment effect, but the question specifically asks about the impact of an increasing drop-out rate.

Sigurd Ramfjord introduced the Periodontal Disease Index a clinical tool that used a periodontal probe , with marks at 3, 6 and 8 mm, to measure the distance from the cemento–enamel junction to the bottom of the pocket (i.e. attachment loss) Ramfjord recommended the assessment of six ‘index teeth’ that soon became known as the ‘Ramfjord teeth’ These teeth were: maxillary right first molar (tooth 16), maxillary left central incisor (tooth 11), maxillary left first bicuspid (tooth 24), mandibular left first molar (tooth 36), mandibular right central incisor (tooth 41) and mandibular right first bicuspid (tooth 44).