Evaluation of Different Dentifrice Compositions for Increasing the Hardness of Demineralized Enamel: An in Vitro Study

In Vitro Models Used in Cariology Mineralisation Research-A Review of the Literature

BACKGROUND

Dental caries remains a significant global health problem. One of the fundamental mechanisms underlying the development and progression of dental caries is the dynamic process of demineralisation/remineralisation. In vitro models have played a critical role in advancing our understanding of this process and identifying potential interventions to prevent or arrest dental caries. This literature review aims to provide a structured oversight of in vitro mineralisation models which have been used to study the tooth demineralisation/remineralisation process.

METHODS

Publications from 2019 to 2023 were screened to identify articles reporting the use of in vitro models to study the demineralisation/remineralisation of tooth caries. The included studies were methodologically assessed for their information on (i) substrate, (ii) lesion formation, and (iii) mineralisation models.

RESULTS

The most reported substrates used in the studies were human teeth along with bovine incisors. Acetic/lactic buffers were the most common solutions to induce caries lesions. pH cycling was the most frequently used mineralisation model for simulating the daily change within the oral environment. This review discussed the advantages and limitations of various approaches.

CONCLUSIONS

Standardisation of in vitro mineralisation models is crucial for enabling effective comparison between studies and advancing caries research.

Effectiveness of fluoride-containing toothpastes associated with different technologies to remineralize enamel after pH cycling: an in vitro study

BACKGROUND

To evaluate the efficacy of fluoride-containing toothpastes with different technologies to remineralize artificial caries lesions in enamel.

METHODS

Bovine enamel blocks were divided into three thirds: intact (untreated), demineralized (artificial caries lesion), and treated (caries lesion, pH cycling with dentifrices). Enamel blocks were randomly distributed into five groups (n = 12): Fluoride-free toothpaste, Colgate Oral Care (NC); Arginine-containing toothpaste, Colgate Total Daily Repair (PC); Silicate-based fluoride toothpaste: REFIX technology, regenerador + sensitive (RDC), NR-5 technology, Regenerate Enamel Science (RES), and NOVAMIN technology, Sensodyne Repair and Protect (SRP). The specimens were submitted to a pH cycling model for 6 days. The efficacy of the toothpastes was estimated by calculating the surface microhardness recovery (%SMHR) and the fluorescence recovery (ΔFRE) with quantitative light-induced fluorescence. The cross-sectional micromorphology of the enamel surface was also assessed using scanning electron microscopy. Elemental analyses (weight%) were determined with an energy-dispersive X-ray spectrometer (EDS). The results were compared to that of the control (NC). Data were statistically analyzed (5%).

RESULTS

%SMHR could be ranked as follows: RDC = PC = RES = SRP > NC. Significantly higher %SMHR and ΔFRE means were observed after enamel treatment with RDC (22.7 and 46.9, respectively). PC (%SMHR = 18.8) was as efficacious as RDC to recover the surface microhardness with a significantly lower mean of ΔFRE (19.5). Only RDC was able to promote the formation of a mineralized layer on the surface of enamel enriched with silicon on the surface.

CONCLUSIONS

The silicate-based fluoride toothpaste containing REFIX technology demonstrated greater efficacy in the remineralizing artificial caries than the other products.

The Influence of Preventive Regimens Containing Different Toothpastes on Caries Risk of High-Risk Patients: A Randomized Clinical Trial

BACKGROUND: The main objective of conservative dentistry is maintaining the health of the dentition and restored teeth free from dental caries. The prevention of dental caries can be achieved by personal prevention programs at home, dental health care professional, and public health application programs. Based on knowledge related to the etiology and pathogenesis of dental caries, this provides a chance for application of effective prevention program for the prevention of dental caries. AIM: This study aimed to evaluate the effect of different preventive regimens using different toothpastes on caries risk using cariogram and decayed, missing, and filled (DMF) scores of high caries risk patients. MATERIALS AND METHODS: The study was conducted on 66 participants with high caries risk. Participants were divided into three groups, 22 participant each. According to the test regimen, where (A1) participants were exposed to a regimen including dual zinc plus arginine-based toothpaste (Colgate total), (A2) participants were exposed to a regimen including zinc-based toothpaste (Crest complete), and (A3) control group was participants that were exposed to a regimen including fluoride-based toothpaste (Signal). The study was carried for 1 year, assessment of cariogram and DMF scores was done in four intervals: T0: baseline, T3: after 3 months, T6: after 6 months, and T12: after 12 months. RESULTS: According to cariogram, there was a statistically significant difference between Groups A1, A2, and A3, where p < 0.001. However, DMF scores of all groups showed no statistically significant difference between the three groups. CONCLUSIONS: Dual zinc plus arginine-based toothpaste is a superior caries preventive regimen in high caries risk patients. CLINICAL SIGNIFICANCE: The benefits of preventive regimen to the practitioner will be providing a non-invasive, and cost-efficient method to prevent dental caries. Benefits to the patient will be an improvement of oral hygiene, prevention of dental caries, and maintain healthy dental supporting structures.

Effects of charcoal-based whitening toothpastes on human enamel in terms of color, surface roughness, and microhardness: an in vitro study

OBJECTIVE

Charcoal based oral care products have gained popularity in the last few years. The aim of this in vitro study was to compare the effects of different charcoal based whitening toothpastes on color, surface roughness and microhardness of human enamel.

MATERIALS AND METHODS

Forty-eight specimens obtained from human permanent upper incisor teeth were randomly divided into 4 groups(n=12):Group-1:Colgate Total 12(CT); Group-2:Body Kingdom(BK); Group-3:Black is White(BW), Group-4:Colgate optic white(COW). Following 4 days cycle of darkening(2-min chlorhexidine and 60-min black tea per day), a 12- week brushing(twice daily for 1 min)was performed. Color of specimens was measured using a spectrophotometer. A contact type profilometer was used to measure surface roughness (Ra) and Vicker's hardness tester was used for the changes in microhardness(VHN). A representative sample from each group was visualized by SEM. Data were analyzed by One-way ANOVA, Welch, Fisher's, Kruskall-Wallis, Wilcoxon Sign Rank and Paired t-tests(p<0.05).

RESULTS

After 12- week brushing, no differences were found among the groups in terms of color change(p=0.989). All toothpastes tested showed no clinically acceptable whitening performances. A substantial increase in surface roughness was found in all groups, except BW(p<0.05). An increase was found in microhardness with CT(p=0.013), while no changes were found with BK, BW and COW(p>0.05).Only few scratches were observed on the enamel surfaces by SEM evaluations.

CONCLUSION

Twelve week brushing with charcoal based whitening toothpastes and a regular fluoridated toothpaste presented similar effects in color of enamel. Surface roughness was increased(except BW) while microhardness was not affected(except CT) with charcoal based whitening toothpastes.

CLINICAL RELEVANCE

Charcoal based whitening toothpastes do not promise to whiten the human permanent teeth and their effects on enamel abrasion should not be disregarded.