Caries-preventing effect of a hydroxyapatite-toothpaste in adults: a 18-month double-blinded randomized clinical trial

Published In: Frontiers in Public Health
Publication Year: 2023

Study Design

This study was a double-blinded, randomized, controlled clinical trial conducted over 18 months. It aimed to compare the caries-preventing effects of a fluoride-free hydroxyapatite toothpaste versus a fluoride toothpaste (1,450 ppm) in an adult population.

Funding Sources

The research was funded by:

• Dr. Kurt Wolff GmbH & Co. KG (Bielefeld, Germany)

• Poznan University of Medical Sciences

• Medical University of Bialystok, Poland

PICO Framework – what was studied and how?

Population:
Adults aged 18–45 years with at least 10 caries-free molars/premolars.

Intervention:
Twice-daily brushing with a fluoride-free hydroxyapatite toothpaste.

Comparison:
Twice-daily brushing with a toothpaste containing 1,450 ppm sodium fluoride.

Outcomes:

• Primary: No increase in Decayed, Missing, and Filled Surfaces (DMFS) index over 18 months.

• Secondary: No change in caries lesions (via DIAGNOcam imaging) and reduced plaque levels (Plaque Control Record - PCR).

In Paragraph Form:
The study investigated whether a fluoride-free hydroxyapatite toothpaste is non-inferior to a standard fluoride toothpaste in preventing dental caries in adults over an 18-month period. Outcomes assessed included changes in DMFS index, caries lesion development using DIAGNOcam imaging, and plaque levels.

Inclusion and Exclusion Criteria

Inclusion Criteria:

• Aged 18–45 years

• At least 10 caries-free molars and premolars

• Willing to use an electric toothbrush

• Provided informed consent

Exclusion Criteria:

• Untreated caries or severe periodontitis

• Orthodontic treatment

• Allergies to toothpaste ingredients

• Systemic or medication-related salivary issues

• Recent participation in other clinical studies

Demographics and Study Design

• Total randomized: 194 participants (97 per group)

• Completed per protocol: 171 participants (87 fluoride group, 84 hydroxyapatite group)

• Mean age: ~23 years

• Gender balance: ~66% female

Primary Outcome Variables and Results

DMFS Index – No Increase (Per Protocol Analysis):

• Hydroxyapatite group: 89.29%

• Fluoride group: 87.36%

• Difference: −1.93%

• 95% CI Upper Bound: 6.84% (well below 20% non-inferiority margin)

• Conclusion: Hydroxyapatite toothpaste was non-inferior to fluoride toothpaste.

Conclusions

Hydroxyapatite toothpaste was found to be equally effective as fluoride toothpaste in preventing caries in adults over 18 months. No statistically significant difference in caries development was observed, supporting hydroxyapatite as a safe, fluoride-free alternative for daily oral care.

Discussion: Strengths and Limitations

Strengths:

• Double-blinded design with a long duration (18 months)

• Direct comparison of active ingredients (identical formulations aside from the active agent)

• Use of modern diagnostic tools like DIAGNOcam

• First study to test hydroxyapatite in a healthy adult population

Limitations:

• Homogeneous, low-risk population (young, healthy adults)

• No dietary monitoring (real-world sugar intake maintained)

• No placebo group due to ethical considerations

• Lack of bitewing X-rays (replaced by transillumination methods)

Visual Aids

Simple Chart: DMFS Score Changes (Primary Outcome)

Citation

Paszynska E, Pawinska M, Enax J, Meyer F, Schulze zur Wiesche E, May TW, Amaechi BT, Limeback H, Hernik A, Otulakowska-Skrzynska J, Krahel A, Kaminska I, Lapinska-Antonczuk J, Stokowska E, Gawriolek M. Caries-preventing effect of a hydroxyapatite-toothpaste in adults: an 18-month double-blinded randomized clinical trial. Front Public Health. 2023 Jul 18;11:1199728. 

Link to article.