Anticariogenic efficacy of a saliva biomimetic in head-and-neck cancer patients undergoing radiotherapy

PREVENTING CARIES AFTER RADIOTHERAPY TO THE HEAD AND NECK REGION - A SYSTEMATIC REVIEW

OBJECTIVES

Radiotherapy to the head and neck region (HN) bears the risk of a rampant development of caries, making intensified prevention necessary. Aim of this systematic review was to summarize the evidence on the efficacy of caries preventive measures in these patients.

METHODS

Clinical studies investigating caries in patients with radiotherapy in the HN with at least 1 caries preventive intervention compared to any control were included. Reports in languages other than English or German were excluded. Records were identified on PubMed, Web of Science, Google Scholar, and Cochrane Library mid-January 2024. Risk of bias was assessed with RoB2. Results were summarized. Planned meta-analyses could not be performed, because of heterogenous data.

RESULTS

Five studies were included, with a total of 355 participants. They were irradiated with up to 70 Gy and received different caries preventive interventions, including sodium fluoride or stannous fluoride gels, remineralizing solutions, an "Intraoral Fluoride Release System" and sucrose restricted diet. Caries score increased between 0.48 DMF-S and 9.2 DF-S per year. Largest differences in caries increments were measured between groups with insufficient and with rigorous fluoride application.

CONCLUSIONS

The main limitations were compromised randomization, heterogeneity of patients and small sample sizes. Clinical studies on caries prevention after radiotherapy to the HN are lacking and the existing ones bear extensive limitations. However, the large effect size and broad consensus suggest the use of fluoride to be indispensable in preventing caries in these patients. The study was funded by the Medical Center - University of Freiburg and was not registered.

Preventive and restorative alternatives to caries by irradiation: a scoping review

PURPOSE

This study is to conduct a comprehensive scoping review to map scientific evidence and clarify concepts regarding the commonly recommended preventive and restorative dental treatments for patients diagnosed with head and neck cancer (HNC) and subjected to radiotherapy.

MATERIAL AND METHODS

This systematic scoping review was performed under the PRISMA-ScR guidelines. The study's experimental design was registered in the Open Science Framework. In vitro studies that evaluated preventive and restorative dental treatment over 50 Gy radiation doses were included. The search was conducted in November 2023 in five electronic databases (PubMed, Scopus, Web of Science, Cochrane Library, and Embase) without language or date restriction. A search strategy was applied based on keywords, MeSh terms, or synonyms. A descriptive analysis was conducted.

RESULTS

A total of 49 studies, out of 3679 original articles identified, were included and reviewed. Of the included studies, three evaluated saliva stimulants and 35 evaluated fluoride-based preventive materials: gel (n = 18) toothpaste (n = 11) mouth rinse (n = 8) and varnish (n = 5) while 14 evaluated restorative materials: resin composite (n = 12) glass ionomer cement (n = 6) and amalgam (n = 1) Of those studies, 36 were clinical trials and 13 were in vitro studies.

CONCLUSION

Fluoride gel was the most frequently recommended preventive material for preventing radiation caries with supportive clinical evidence. Resin composite and glass ionomer were the most frequently used restorative materials, respectively. However, there is not yet clinical evidence to support the use of resin composite in irradiated teeth.

Remineralisation of enamel and dentine with stabilised stannous fluoride dentifrices in a randomised cross-over in situ trial

OBJECTIVES

To compare the remineralisation efficacy and ion bioavailability of two novel SnF2-containing dentifrices in a blinded, cross-over, randomised in situ clinical study.

METHODS

Six participants wore removal palatal appliances holding human enamel and dentine blocks with subsurface lesions. Appliances were worn for two treatment periods of 14 consecutive days each, with a one-week washout period in-between. Participants were randomly allocated to rinse with a 1:5 diluted coded slurry of one of two dentifrices containing either 5 % casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) +1100 ppm F as SnF2 [MIPOP], or 1100 ppm F as SnF2 [CT], for 1 min, four times a day. Saliva was collected post-treatment and analysed for tin, calcium, inorganic phosphate and fluoride ions using atomic absorption spectrophotometry and ion chromatography. Enamel and dentine lesions were analysed for percent remineralisation (%R) using transverse microradiography and percent surface microhardness recovery (%SMHR).

RESULTS

MIPOP released significantly higher F (3.00 ± 0.27 mM), Ca (15.23 ± 3.23 mM) and Sn (1.18 ± 0.13 mM) into saliva whereas CT released 2.89 ± 0.32 mM F and only 0.84 ± 0.11 mM Ca and 0.28 ± 0.10 mM Sn. MIPOP produced significantly higher %R than CT: 25.6 ± 1.5 % compared to 15.2 ± 0.7 % in enamel, and 33.6 ± 3.1 % compared to 20.6 ± 1.1 % in dentine. Additionally, MIPOP produced significantly higher %SMHR (18.2 ± 7.9 %) compared to CT (4.1 ± 0.6 %).

CONCLUSIONS

Both dentifrices promoted remineralisation, but the MIPOP dentifrice with added CPP-ACP and the ion-stabilising effects of CPP released higher amounts of bioavailable tin and produced significantly higher remineralisation and surface microhardness recovery.

CLINICAL SIGNIFICANCE

Modern dentifrices contain SnF2 for a range of oral health benefits. Challenges associated with stability of these formulations can affect ion bioavailability, reducing efficacy. Two dentifrices with SnF2 promoted remineralisation in situ, however the dentifrice with the added saliva biomimetic CPP-ACP was superior and therefore may produce greater health benefits.

Management of Oral Hygiene in Head-Neck Cancer Patients Undergoing Oncological Surgery and Radiotherapy: A Systematic Review

BACKGROUND

In the literature, among oral health prevention programs dedicated to cancer patients, a wide heterogeneity is evident. The purpose of this work is to analyze the available scientific evidence for the treatment of head and neck cancer (HNC) patients undergoing resective surgery and radiotherapy and to draw up a diversified oral hygiene protocol during oncological therapy.

METHODS

PubMed was used as database. Studies published from 2017 to September 2022 were analyzed. Studies investigating the effectiveness of the preventive procedures carried out by the dental professionals in HNC patients undergoing postoperative adjuvant therapy have been taken into account.

RESULTS

The application of the search string on PubMed allowed the selection of 7184 articles. The systematic selection of articles led to the inclusion of 26 articles in this review, including 22 RCTs, 3 observational studies, and 1 controlled clinical study. Articles were divided according to the debated topic: the management of radiation-induced mucositis, xerostomia, the efficacy of an oral infection prevention protocol, and the prevention of radiation-induced caries.

CONCLUSIONS

Dental hygienists are fundamental figures in the management of patients undergoing oncological surgery of the maxillofacial district. They help the patient prevent and manage the sequelae of oncological therapy, obtaining a clear improvement in the quality of life.

Evaluation of the changes in physical properties and mineral content of enamel exposed to radiation after treating with remineralization agent

OBJECTIVE

The aim of this study was to investigate the effect of different remineralization agents on the physical properties and elemental content of enamel exposed to radiation.

MATERIAL AND METHOD

The enamel surfaces of impacted third molar teeth were prepared, and six study groups were created (n = 6). Next, 60 Gy radiation was applied to each group. Between applications, each group except for the control group was treated with a different remineralization agent (sodium fluoride, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), casein phosphopeptide amorphous calcium phosphate with fluorite (CPP-ACFP), bioactive glass, or chitosan). The results were evaluated in terms of pre- and post-radiation values and the difference between the two. The paired-samples t test and analysis of variance test were used in the analysis of normally distributed hardness and roughness values, while Wilcoxon's signed ranks test, and the Kruskal Wallis and Mann-Whitney U tests were used in the analysis of elemental content without normal distribution.

RESULTS

A statistically significant decrease was observed in microhardness measurements in all groups. Intragroup evaluation revealed a statistically significant difference between the NaF and bioactive glass groups (p < 0.05). No significant difference was observed between the groups' roughness measurements (p < 0.05). Intergroup evaluation of surface roughness revealed a significant difference in the CPP-ACFP and chitosan groups (p < 0.05). Pre- and post-radiation oxygen, magnesium, and potassium levels and Ca/P ratios also differed significantly (p < 0.05).

CONCLUSION

Radiation caused a statistically significant difference in the microhardness and elemental content of enamel. However, no significant difference was observed in enamel roughness. The applied remineralizing agents have a partial ameliorating effect on the adverse impacts of radiation.

CLINICAL RELEVANCE

Radiation causes changes in the mechanical properties and elemental content of tooth enamel. Remineralizing agent application is a promising option in reducing the adverse effects of irradiation.

The Effect of Long-Term Antihypertensive Therapy on the Change in Secretion and Calcium, Bicarbonate and Phosphate Ion Concentration in Non-Stimulated and Stimulated Saliva

Objective

The aim of this study was to evaluate the amount of saliva secreted and calcium, bicarbonate, and phosphate ion concentration in patients receiving antihypertensive for five years or over five years (patient group) and in healthy patients (control group).

Material and methods

The patient or experimental group included 31 subjects who were admitted to a cardiovascular clinic and had been receiving an antihypertensive drug therapy for more than five years. The control group included 31 healthy subjects. The measured amount of saliva was further used to determine the calcium, phosphate and bicarbonate ion concentration values. Calcium and phosphate ions were determined spectrophotometrically, while bicarbonate ions were determined by titration.

Results

A two-way-test (Student's test) was used to compare the values of variables. The amount of excreted saliva was statistically significantly lower in the patient group in non-stimulated (1.739 mL/5 min) and stimulated saliva (3.594 mL/5 min). Calcium ion concentration was statistically significantly lower in patient group in resting saliva (6.143 mg/dL). Bicarbonate and phosphate ion concentration in patient group was statistically significantly higher in non-stimulated (bicarbonate ion = 14.041 mmol/L, phosphate ion = 2.818 μmol/L) and stimulated saliva (bicarbonate ion = 10.872 mmol/L, phosphate ion = 1.454 μmol/L), respectively.

Conclusion

A reduced amount of saliva and calcium ion concentration indicates the possibility of a higher frequency of hard dental tissue demineralization process. On the contrary, the increase in the phosphate and bicarbonate ion concentration in the patient group affects the regulation of acid-base balance, thus having a preventive effect.

Addition of CPP-ACP to yogurt inhibits enamel subsurface demineralization

OBJECTIVES

The aim of this study was to investigate the capacity of an approved food additive with anticariogenic properties, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), when added to a processed, sugar-containing yogurt with added lactic-acid bacteria (probiotics), to prevent demineralization of enamel subsurface lesions in vitro.

METHODS

Enamel subsurface demineralised lesions were created in thirty extracted human third molars. These were then exposed to artificial saliva (AS) with: 1) Danone yogurt alone; 2) Danone yogurt with 0.2 % w/w CPP-ACP; or 3) Danone yogurt with 0.5 % w/w CPP-ACP at 37 °C for two weeks. The yogurt/AS was replaced with fresh preparations each day. At the completion of each treatment the enamel slabs were embedded, sectioned and analyzed using transverse microradiography to measure changes in enamel lesion depths and subsurface mineral content. Yogurt samples were analysed for soluble calcium (Ca) and inorganic phosphate (Pi) levels and pH.

RESULTS

Yogurt alone demineralized enamel subsurface lesions to produce significantly larger lesions. However, the addition of 0.2 % CPP-ACP to the yogurt resulted in significant reduction in demineralization compared with yogurt alone (p < 0.0001). The addition of 0.5 % CPP-ACP to the yogurt produced a net remineralization effect with a significant increase in lesion mineral content (p < 0.0001). The addition of CPP-ACP resulted in a significant (p < 0.0001) dose-related increase in Ca, Pi and pH.

CONCLUSIONS

The addition of CPP-ACP to a commercial yogurt exhibited a dose related protective effect with 0.5 % CPP-ACP producing remineralization of existing enamel subsurface lesions under the in vitro experimental conditions. CLINICAL SIGNIfiCANCE: The results of this study suggest that some processed yogurts with added sugar could result in enamel demineralization when frequently consumed by individuals with poor oral hygiene. The addition of CPP-ACP to these yogurts may help prevent demineralization and promote enamel subsurface lesion remineralization, and therefore, make them safer for teeth.

Remineralization and fluoride uptake of white spot lesions under dental varnishes

INTRODUCTION

The aim of this study was to evaluate white spot lesion (WSL) remineralization and fluoride uptake by the application of fluoride varnishes directly onto artificial WSLs in vitro.

METHODS

MI varnish containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and 2.26% fluoride and Duraphat varnish containing 2.26% fluoride (no added calcium) were compared with a placebo varnish (no added calcium or fluoride). Two WSLs were prepared in enamel slabs and varnish applied to cover one of the two lesions. Each slab was immersed in artificial saliva for 14 days at 37°C. Mineral content was determined using transverse microradiography and fluoride uptake using electron probe microanalysis. The data were statistically analysed using a linear mixed model.

RESULTS

Both MI and Duraphat varnishes significantly remineralized the covered and uncovered WSLs when compared with the placebo varnish (P < 0.001). The WSLs covered with varnish showed greater remineralization than those uncovered. MI varnish produced the highest level of remineralization and significantly greater fluoride uptake (0.44 ± 0.08 wt%) compared with Duraphat (0.24 ± 0.03 wt%) and the placebo varnish (0.06 ± 0.05 wt%).

CONCLUSION

Varnish containing fluoride and CPP-ACP was superior to varnish containing fluoride alone in promoting WSL remineralization and fluoride uptake.