In vitro-in situ comparison study

A comparison between in vitro and randomized in situ models for remineralization of artificial enamel lesions

Jablonski-Momeni A, Lentz J, Jablonski B, Kiesow A, Morawietz M. Sci Rep. 2024 Oct 25;14(1):25295. 
doi: 10.1038/s41598-024-76387-w. 

The randomized study aimed to evaluate the comparability of in situ (iS) and in vitro (iV) study protocols regarding remineralization of artificial enamel lesions. Two toothpastes (group A: 1450 ppm sodium fluoride, group B: placebo 0 ppm F-), were investigated. IV, a pH-cycling model with toothpaste slurry treatment was applied for 10d. IS, remineralization was performed in 9 participants wearing splints with embedded enamel samples for 10 and 21d, randomly allocated to groups A and B. Samples were scanned by X-ray micro-computed tomography (μCT) and grayscale value line profiles corresponding to mineral density (rel.ΔZ) were analyzed. 
T-Test for dependent and independent data and analysis of variance (ANOVA) were used for further analyses (α = 0.05). 
Rel.ΔZ of fluoride treated samples (A) were iV = 40.2%, iS 10d = 11.5% and iS 21d = 46.1% (p > 0.05). Rel.ΔZ of placebo treated samples (B) were: iV = − 6.2%, iS 10d = 25.2% and iS 21d = 11.0% (p > 0.05). Remineralization potential of both toothpastes was significantly different regarding iV (p < 0.001) and iS after 21d (p = 0.034), while in case of iS 10d no significant difference was detected (p = 0.4). Despite different study protocols the μCT results after remineralization were comparable between iV and iS. 
The results suggest that selected studies can be carried out in faster, simplified iV studies using pH-cycling instead of iS studies.

The data set presents the data which were used for the analysis.

iV = in vitro
iS = in situ

iV 10d = analysis of iV tooth slabs after 10 days
iS 10d = analysis of iS tooth slabs after 10 days
iS 21d = analysis of iS tooth slabs after 21 

μCT = X-ray micro-computed tomography

deltaZ Demin: delta gray values after demineralization, arbitrary units	
deltaZ Remin: delta gray values after remineralization, arbitrary units
rel.DeltaZ = relative difference of the measured areas, %

Group
A: fluoridated toothpaste, 1450 ppm (parts per million) sodium fluoride
B: placebo toothpaste, 0 ppm (parts per million) fluoride
C: Control, no toothpaste (only in vitro)