This randomized double-blind two arm controlled clinical trials evaluates the hypothesis that the regular use of a tooth paste containing microcrystalline hydroxylapatite provides a caries preventive effect in caries-susceptible individuals undergoing orthodontic therapy with fixed appliances which is comparable to the caries preventive effect provided by the regular use of a fluoridated tooth paste.

Introduction

According to the criteria of evidence based medicine the use of fluoridated tooth paste as well as fluoridated mouth rinses are,with the exception of dietary control, the only proven measures for the prevention of dental caries.

Aim, Study Hypothesis

The aim of this randomized double-blind, two arm, controlled clinical trial is evaluation of the hypothesis that the regular use of a tooth paste containing microcrystalline particles of hydroxylapatite in caries-active subjects under orthodontic therapy with fixed appliances will provide at least a comparable extent of caries prevention as the regular use of fluoridated tooth paste during an observation period of 6 months.

Material and Methods

Study subjects will be recruited from juveniles and young adults, age 12-25, displaying high (≥105 CFU) salivary counts of caries promoting mutans streptococci and seeking orthodontic therapy with fixed appliances. Evaluated parameters are the presence of enamel caries on the buccal aspects of teeth 15-25 according to the criteria of the International Caries Detection and Assessment System (ICDAS), the presence of gingival inflammation assessed by the Gingival Index (GI) the presence of microbial plaque on the evaluated teeth assessed by the Plaque Index (PlI) and the extent of mutans streptococci colonization (MS) on the evaluated teeth and in saliva using standardized cultivation techniques. Primary endpoint of the study is the number and severity of enamel caries lesions according to the ICDAS classification. Exclusion criteria are the presence of ICDAS lesion ≥ 3 on the buccal surfaces of teeth 15-25, the presence of gingival lesions > GI 2 and the regular use of salivary flow-reducing medications.

At baseline, ICDAS scores, as well as GI, PlI and MS will be recorded followed by the incorporation of the fixed orthodontic appliances. Subsequently, using a random list participants are provided with a standardized electric tooth brush and a supply of one of the two experimental tooth pastes (hydroxylapatite(HA)/fluoride (FL)) to be used 2 x daily for the next 6 months. HA-tooth paste contains no fluoride, FL-tooth paste contains stannous fluoride and amine fluoride. At days 28, 84 and 168 (end of study) ICDAS, GI, PlI and MS are recorded again. Additionally all study participants will receive a full mouth preventive professional supragingival tooth cleaning followed by the application of a 1% chlorhexidine gel on all tooth surfaces once every 4 weeks during the course of the trial.

Inclusion Criteria:

• Healthy juveniles and young adults with caries-promoting mutans streptococci colonization seeking orthodontic therapy with fixed orthodontic appliances

Exclusion Criteria:

• Oral ulcers
• Caries lesions on the buccal aspects of teeth 15-25
• Unrestored caries on any tooth
• Regular use of medications interfering with salivary flow and/or gingival inflammation