Dental demineralization and caries in patients with head and neck cancer

Effect of 70 Gy tumor therapeutic radiation applied intermittently or directly on microcosm biofilm composition and dental hard tissues and its potential to cause dental caries

OBJECTIVES

This study compared total (70 Gy, one session) and intermittent (35 sessions of 2 Gy) tumor radiation protocols on tooth morphology (n=5) using Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX) and on microcosm biofilm microbiota (n=12) through colony-forming unit (CFU) counts for Candida spp., total microorganisms, Streptococcus mutans, and total lactobacillus. It also assessed "radiation caries" development via Transverse Microradiography (TMR, n=12).

METHODS

Bovine enamel and root dentin were divided into three groups (n=17): total radiation (1); intermittent radiation (2); and no radiation-control (3). Biofilm was produced using saliva from irradiated (for 1 and 2) or non-irradiated patients (for 3) (n=3 donors) combined with McBain saliva with 0.2 % sucrose for 5 days. Data were analyzed using ANOVA/Tukey, t-test, and Kruskal-Wallis/Dunn's tests (p<0.05).

RESULTS

S. mutans and Candida spp. were observed on irradiated dentin compared to control, but these microorganisms were absent in enamel biofilm (S. mutans only in 50 % and 12.5 % of intermittent and total irradiated enamel). Total microorganisms and lactobacillus numbers were similar between groups, except for total microorganisms in irradiated enamel vs. control (p<0.037). No significant differences in mineral loss or lesion depth were detected between protocols or tissues (p>0.05). SEM-EDX revealed slight differences in magnesium (p=0.0439) and calcium (p=0.0216) content in intermittently irradiated dentin.

CONCLUSIONS

Despite increased cariogenic microorganisms in irradiated biofilm, no greater susceptibility to "radiation caries" was observed under this model.

CLINICAL SIGNIFICANCE

Although the radiotherapy alters oral microbiota and dental tissue morphology, these changes alone do not increase radiation-induced caries risk. Other factors, as salivary changes and diet, need to be better studied.

The Oral Microbiome and Cancer

There is growing evidence suggesting a strong association between members of the oral microbiota and various types of cancer, including oral cancer, colorectal cancer, esophageal squamous cell carcinoma, and pancreatic cancer. Periodontal diseases closely associated with pathogenic bacteria in the oral cavity have been shown to be correlated with the occurrence and development of cancers. Among the periodontal disease-associated bacteria in the oral cavity, two prominent oral pathogens, Porphyromonas gingivalis and Fusobacterium nucleatum, have been found to promote tumor cell proliferation, invasion, and migration, as well as to inhibit immune cell function, thereby facilitating tumor progression. The presence of other oral pathogenic bacteria, such as Treponema denticola, Tannerella forsythia, Parvimonas micra, and Aggregatibacter actinomycetemcomitans, has also been found to be associated with cancer worsening. Oral commensal bacteria play a crucial role in maintaining the normal oral homeostasis. However, the relationship between oral commensal bacteria and the occurrence and development of cancers remains controversial. Some studies suggest an increase in oral commensal bacteria during tumor development, while others suggest an association of certain commensal bacteria with lower tumor risk. The microbiota can significantly alter responses and toxicity to various forms of cancer treatment through interactions with the human body, thereby influencing disease progression. In this chapter, we provide a concise overview of current understanding of the role of the oral microbiota in cancer.

The influence of different radiotherapy doses on the mechanical properties and microstructure of the enamel and dentin of human premolar teeth

OBJECTIVE

Radiation therapy is applied in the treatment of head and neck cancer patients. However, oral-health-related side effects like hyposalivation and a higher prevalence of caries have been shown. This study aims to assess the influence of different radiotherapy doses on the mechanical properties, roughness, superficial microstructure, and crystallinity of the enamel and dentin of human premolar teeth.

METHODS

Specimens (n = 25) were categorized into five groups based on the radiation dose received (0, 10, 30, 50, and 70 Gy). The enamel and dentin of these specimens were subjected to a microhardness tester, profilometer, atomic force microscopy (AFM), scanning electron microscopy (SEM), and X‑ray diffraction (XRD) before and after different irradiation doses and compared to hydroxylapatite in each group. The data were analyzed using repeated-measures analysis of variance (ANOVA).

RESULTS

Therapeutic radiation doses of 30, 50, and 70 Gy led to a decrease in the microhardness and an increase in the average roughness of the enamel, and rougher surfaces were observed in the mixed three-dimensional images. Moreover, in the dentin, a similar outcome could be observed for more than 10 Gy. The main crystalline phase structure remained hydroxylapatite, but the crystallinity decreased and the crystalline size increased above 10 Gy. The superficial micromorphology revealed granulation, fissures, and cracks in a dose-dependent manner. Radiation below 70 Gy had little effect on the hydroxylapatite concentration during the whole experiment.

CONCLUSION

Above a radiation dose of 30 Gy, the micromorphology of the tooth enamel changed. This occurred for dentin above 10 Gy, which indicates that dentin is more sensitive to radiotherapy than enamel. The radiation dose had an effect on the micromorphology of the hard tissues of the teeth. These results illustrate the possible mechanism of radiation-related caries and have guiding significance for clinical radiotherapy.

Consequences of hyposalivation in relation to cancer treatment and early management of radiation-induced caries: case reports

Given the prevalence of head and neck carcinoma and the salivary changes induced by the oral side effects of radiotherapy, such patients are at higher risk/susceptibility of developing dental caries. Radiation-caries is often under-treated in patients undergoing cervicofacial radiotherapy, yet these lesions can increase the risk of osteoradionecrosis due to necessary subsequent dental extractions. Moreover, xerostomia is accompanied by difficulties with speech, chewing and swallowing. The prevention and/or early management of radiation-induced carious lesions is essential in preventing oral complications and improving patients' quality of life. Based on a French case series, this paper proposes a protocol for the dental management of radiation-induced carious lesions.

Use of oral nutritional supplements in irradiated patients with head and neck cancer

OBJECTIVES

Malnutrition is common among patients with head and neck cancer (HNC) and associated with poorer outcomes. Oral nutritional supplements (ONS) are often prescribed, with concerns raised about their cariogenicity. This study examined ONS use and caries experience in patients with HNC 12 months post-diagnosis.

METHODS

Fifty-four patients with HNC referred for pre-radiotherapy dental assessment were recruited. Data collected included: age, gender, residential postcode, smoking, alcohol use, HNC characteristics, dental history, oral hygiene habits, dietary advice and ONS use. Data was collected at diagnosis, during radiotherapy and 6 weeks, three, six- and 12-months post-treatment completion.

RESULTS

Fifty-one subjects completed the study. 76.5% of the participants used ONS for an average of 13.8 weeks. Caries developed in 22.9% of ONS users and 11.1% of non-users (p = 0.6585). The mean overall duration of ONS use was 18.7 weeks for the caries group and 8.5 weeks for the caries-free group (p = 0.1507). Lack of collaboration and disconnection was noted between dietary advice given by dieticians and dentists.

CONCLUSIONS

ONS use is common among patients with HNC. Larger studies are needed to establish the reasons for caries development and impacts of ONS use on oral health. Importance of multidisciplinary management of malnutrition is highlighted.

Updates on Caries Risk Assessment-A Literature Review

This narrative review aims to provide an update on caries risk assessment (CRA) and the available CRA tools. CRA can be used to monitor the status of oral care, as well as for documentation and research purposes. Caries risk is determined by the interplay of risk and protective factors. Common risk factors include suboptimal oral hygiene practices, previous caries experience, low plaque acidity, frequent snacking, cariogenic diet, enamel defects, reduced salivary flow, polypharmacy, and radiotherapy experience. Caries risk can be reduced through some preventive measures, such as the use of fluoride, gum chewing, dental sealants. The CRA process can be categorized as single or multifactor tools. Single-factor CRA tools include diet analysis questionnaires, cariogenic bacteria testing and saliva testing kits, whereas multifactor CRA tools encompass Caries Management by Risk Assessment (CAMBRA), Cariogram, and PreViser. Some CRA tools may quantify risk and protective factors to compute caries risk. Additionally, they can generate visual and educational presentations that foster success in oral care. Clinicians consider CRA beneficial for developing personalized care plans. However, the literature fails to reflect this and reveals limited studies supporting its use as evidence-based practice for caries management.

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.

In vitro effect of TiF4/NaF solution on the development of radiation-induced dentin caries

OBJECTIVE

To evaluate the protective effect of an experimental solution containing TiF4/NaF on the development of radiation-induced dentin caries lesions.

METHODOLOGY

bovine root samples were irradiated (70Gy) and distributed as following (n=12/group): Commercial Saliva (BioXtra), NaF (500 ppm F-), TiF4 (500 ppm F), TiF4/NaF (TiF4: 300 ppm F-, NaF: 190 ppm F-), and Phosphate buffer solution (PBS, negative control). Biofilm was produced using biofilm from irradiated patients and McBain saliva (0.2% of sucrose, at 37oC and 5% CO2) for five days. The treatments were applied 1x/day. Colony-forming units (CFU) were counted and demineralization was quantified by transversal microradiography. The ANOVA/Tukey test was applied for all parameters.

RESULTS

All treatments reduced CFU for total microorganisms. TiF4 reduced Lactobacillus sp. (7.04±0.26 log10 CFU/mL) and mutans streptococci (7.18±0.28) CFU the most, when compared to PBS (7.58±0.21 and 7.75±0.17) and followed by NaF (7.12±0.31 and 7.34±0.22) and TiF4/NaF (7.16±0.35 and 7.29± 0.29). TiF4 and Commercial saliva showed the lowest integrated mineral loss (ΔZ-vol%.mm) (1977±150 and 2062±243, respectively) when compared to PBS (4540±335), followed by NaF (2403±235) and TiF4/NaF (2340±200). Commercial saliva was the only to significantly reduce mineral loss (LD-µm) (111±25) compared to PBS (153±24).Mean mineral loss (R-vol%) decreased by 35.2% for TiF4 (18.2±3.3) when compared to PBS (28.1±2.9) Conclusion: TiF4/NaF has a comparable anti-cariogenic effect to TiF4 and Commercial saliva under the model in this study.

Qualitative Classification of Late Systemic Symptoms in Head and Neck Cancer Survivors

Improved rates of cancer control have increased the head and neck cancer survivor population. Cancer survivorship clinics are not widely available in the USA, and longitudinal supportive care for patients undergoing multimodal therapy has not advanced at a pace commensurate with improvements in cancer control. Consequently, a large head and neck cancer survivor population whose quality of life may be chronically and/or permanently diminished presently exists. This lack of awareness perpetuates under-recognition and under-investigation, leaving survivors' (mostly detrimental) experiences largely uncharted. We conducted a qualitative exploration of survivors' experiences, aiming to unpack the profound impact of late systemic symptoms on daily life, encompassing work, relationships, and self-identity in the head and neck cancer survivor community. The study included 15 remitted head and neck survivors, ≥12 months from their final treatment, who participated in semi-structured interviews conducted by a medical oncologist. Data analysis comprised qualitative thematic analysis, specifically inductive hierarchical linear modeling, enriched by a deductive approach of anecdotal clinical reporting. Results highlighted that 43.36% of all quotation material discussed in the interviews pertained to chronic emotion disturbance with significant implications for other domains of life. A central symptom cluster comprised impairments in mood/emotions, daily activity, and significant fatigue. Dysfunction in sleep, other medical conditions, and cognitive deficits comprised a secondary cluster. Physical dysfunctionality, encompassing pain, appetite, and eating, and alterations in experienced body temperature, constituted a tertiary cluster, and perhaps were surprisingly the least discussed symptom burden among head and neck cancer survivors. Symptoms causing heightened long-term survivor burden may be considered epiphenomenal to central physical dysfunctionality, albeit being presently the least represented in cancer survivor care programs. Moving forward, the development of targeted and multi-dimensional treatment programs that encompass physical, psychosocial, and spiritual domains are needed to increase clinical specificity and effective holistic long-term solutions that will foster a more compassionate and informed future of care for the cancer survivorship community.

Antibacterial, antibiofilm and anticaries effect of BioXtra® mouthrinse for head and neck cancer (HNC) patients under a microcosm biofilm model

BACKGROUND AND PURPOSE

Considering the lack of studies investigating salivary substitutes to control post-radiation caries for patients with head and neck cancer (HNC), this study aimed to evaluate the antibacterial, antibiofilm, and anticaries effects of BioXtra® on the microcosm biofilm formed on different enamel types (non-irradiated and irradiated) and from distinct saliva sources (control and HNC patients).

MATERIALS AND METHODS

Non-irradiated and irradiated enamel specimens were treated with BioXtra®, phosphate-buffered-saline (PBS; negative control), or 0.12% chlorhexidine (CHX; positive control) for 1 min. Biofilm was produced from human saliva (healthy participants with normal salivary flow for the control group or irradiated HNC patients with hyposalivation for the HNC group), mixed with McBain saliva, under 0.2% sucrose exposure, daily submitted to the treatments (1 min), for 5 days. Bacterial metabolic activity, biofilm viability, CFU counting, and enamel demineralization were determined.

RESULTS

BioXtra® significantly reduced the bacterial metabolic activity for both enamel types and the inoculum sources, being more effective for the irradiated enamel or for the saliva from the control group. Similarly, BioXtra® significantly reduced the biofilm viability, the CFU for total microorganisms, mutans streptococci, and lactobacilli, and was able to significantly reduce the mineral loss and the lesion depth compared to PBS. CHX was an effective treatment to significantly reduce all parameters, performing better than BioXtra® and reinforcing its reliable efficiency as a positive control.

CONCLUSION

Regardless of the enamel type and the inoculum source, BioXtra® presented antibacterial, antibiofilm, and anticaries effects under this experimental model, which should be confirmed in further clinical studies.

Oral care and the use of fluoride in the prevention of radiation-related caries: A scoping review

OBJECTIVE

This scoping review aimed to map the literature on oral hygiene protocols and fluoride use in patients undergoing radiotherapy.

STUDY DESIGN

A comprehensive search was performed in 10 databases, including part of the "gray literature." Clinical trials and observational studies that used radiotherapy in the head and neck region and evaluated the occurrence of radiation-related caries (RRC) were included.

RESULTS

Twenty-one studies were included in the review. The studies generally presented different methods of oral care and fluoride use. Several studies have shown promising results for oral care instructions in preventing RRC. The main strategies found in the articles were oral hygiene instructions, professional teeth cleaning, recommendations for the use of fluoride toothpaste, and monthly follow-ups. Fluoride gel was the most commonly used fluoride product (72%). Its main recommendation for use was at least 5 min at night daily. Most of these studies (60%) used custom-made trays. Other fluoride methods were fluoride varnish, mouthrinses, and high-fluoride-containing toothpaste.

CONCLUSION

Oral care, such as hygiene instructions with regular dental follow-up and daily fluoride, seem to be promising strategies for preventing RRC. Periodically monitoring these patients is one of the most important strategies.

Erosion-inhibiting potential of the stannous fluoride-enriched CPP-ACP complex in vitro

Currently available anti-erosive agents only provide partial protection, emphasizing the need to enhance their performance. By characterizing erosive enamel wear at the nanoscale, the aim of this in vitro study was to assess the anti-erosive effects of SnF₂ and CPP-ACP both individually and synergistically. Erosion depths were assessed longitudinally on 40 polished human enamel specimens after 1, 5, and 10 erosion cycles. Each cycle comprised one-min erosion in citric acid (pH 3.0) and one-min treatment in whole saliva (control group) or a slurry of one of the three anti-erosive pastes (10% CPP-ACP; 0.45% SnF₂ (1100 ppm F); or SnF₂/CPP-ACP (10% CPP-ACP + 0.45% SnF₂)) (n = 10 per group). Scratch depths were assessed longitudinally in separate experiments using a similar protocol after 1, 5, and 10 cycles. Compared with the control groups, all slurries reduced erosion depths after 1 cycle (p ≤ 0.004) and scratch depths after 5 cycles (p ≤ 0.012). The order of anti-erosive potential was SnF₂/CPP-ACP > SnF₂ > CPP-ACP > control for erosion depth analysis, and SnF₂/CPP-ACP > (SnF₂ = CPP-ACP) > control for scratch depth analysis. These data provide 'proof of concept' evidence that SnF₂/CPP-ACP has superior anti-erosive potential compared to SnF₂ or CPP-ACP alone.

Oral Implications of Polypharmacy in Older Adults

Over the next several decades, rates of aged populations will increase rapidly. These populations are susceptible to multimorbidities and polypharmacy (concurrently, prescribed 5 or more medications). Many medications have side effects that manifest orally. Therefore, it essential to possess current pharmacologic knowledge to diagnose and treat oral implications of commonly prescribed medications. This article details common medication-induced oral lesions and patient assessment of risk factors for polypharmacy and provides a template to integrate medication reconciliation into dental clinical practice.

Effect of Cumulative Ionizing Radiation on Flexural Strength, Flexural Modulus, and Elasticity Modulus of Dentin in Unerupted Human Third Molars

Purpose

This in vitro study aimed to investigate the changes in mechanical properties in dentin of third molars after radiation therapy using variable doses and frequencies.

Methods and Materials

Rectangular cross sectioned dentin hemisections (N = 60, n = 15 per group; >7 × 4 × 1.2 mm) were prepared using extracted third molars. After cleansing and storage in artificial saliva, random distribution was performed to 2 irradiation settings, namely AB or CD (A, 30 single doses of irradiation [2 Gy each] for 6 weeks; B, control group of A; C, 3 single doses of irradiation [9 Gy each]; and D, control group of C). Various parameters (fracture strength/maximal force, flexural strength, and elasticity modulus) were assessed using a universal Testing Machine (ZwickRoell). The effect of irradiation on dentin morphology was evaluated by histology, scanning electron microscopy, and immunohistochemistry. Statistical analysis was performed using 2-way analysis of variance and paired and unpaired t tests at a significance level of 5%.

Results

Significance could be found considering the maximal force applied to failure when the irradiated groups were compared with their control groups (A/B, P < .0001; C/D, P = .008). Flexural strength was significantly higher in the irradiated group A compared with control group B (P < .001) and for the irradiated groups A and C (P = .022) compared with each other. Cumulative radiation with low irradiation doses (30 single doses; 2 Gy) and single irradiation with high doses (3 single doses; 9 Gy) make the tooth substance more prone to fracture, lowering the maximal force. The flexural strength decreases when cumulative irradiation is applied, but not after single irradiation. The elasticity modulus showed no alteration after irradiation treatment.

Conclusions

Irradiation therapy affects the prospective adhesion of dentin and the bond strength of future restorations, potentially leading to an increased risk of tooth fracture and retention loss in dental reconstructions.

Factors Influencing the Survival Rate of Teeth and Implants in Patients after Tumor Therapy to the Head and Neck Region-Part 1: Tooth Survival

We aimed to evaluate possible factors influencing the long-term survival of teeth after tumor therapy (TT) to the head and neck region with and without radiation. Between January 2019 and January 2020, patients who underwent TT for head and neck cancer and received dental treatment before and after TT at the Department of Prosthetic Dentistry of the Martin Luther University Halle-Wittenberg were enrolled in the study. Clinical examination with assessment of dental status and stimulated salivary flow rate (SFR) was performed and information about disease progression and therapy was retrieved from medical records. Of 118 patients (male: 70.3%; mean age: 63.2 ± 12.4 years), 95 received radiotherapy (RT), and 47 were administered radio-chemotherapy (RCT). The teeth of irradiated patients exhibited a lower 5-year survival probability (74.2%) than those of non-irradiated patients (89.4%). The risk of loss (RL) after RT increased with nicotine use, presence of intraoral defects, reduced SFR, RCT and regarding mandibular teeth, and decreased with crowning following TT. Lower SFR increased the RL even without RT. Consideration of patient's treatment history, individual risk profile, and clinical findings during the prosthetic planning phase could enable earlier, more targeted dental treatment after TT (e.g., timely crowning).

The Effects of Radiotherapy on Microhardness and Mineral Composition of Tooth Structures

OBJECTIVE

 The purpose of this study was to evaluate the microhardness and mineral composition alterations in enamel and dentine after radiotherapy.

MATERIALS AND METHODS

 Forty human maxillary premolar teeth (20 pairs) were assigned to nonirradiated and irradiated groups, the latter irradiated by fractional radiation to achieve a total dose of 70 Gy. Microhardness measurement was performed on a Knoop microhardness tester. Chemical components were analyzed using energy dispersive spectroscopy and Fourier transform Raman spectroscopy. The morphology was observed using a scanning electron microscope. The microhardness data were analyzed using a paired t-tested and one-way repeated analysis of variance (ANOVA), and the mineral composition data using related-samples Wilcoxon signed rank test and related-samples Friedman's two-way ANOVA by ranks.

RESULTS

 The irradiated teeth had a significantly lower microhardness in both enamel and dentine compared with the nonirradiated teeth. The irradiated dentine at 50 μm from the external tooth surface at the cemento-enamel junction showed the lowest microhardness compared with other locations. There was no statistically significant difference in calcium:phosphate ratio and chemical components. There was a reduction in protein:mineral ratio in dentine and at the cemento-enamel junction after irradiation. The irradiated teeth exhibited crack lines at the dentine-enamel junction and in dentine.

CONCLUSION

 Fractional radiation reduced microhardness in both enamel and dentine. The cervical dentine exhibited the highest microhardness reduction compared with other enamel and dentine locations.

Salivary Gland Dysfunction Secondary to Cancer Treatment

The number of cancer survivors are increasing and so are the oral toxicities from cancer therapy. Most patients receiving treatment for cancer develop some form of oral adverse events including, but not limited to, mucositis, opportunistic infections, dry mouth, and/or osteonecrosis of the jaw. One of the most common complications from head and neck cancer radiation therapy is salivary gland dysfunction (SGD). SGD is an umbrella term that includes the subjective sensation of dry mouth (xerostomia) and hyposalivation (objective reduction of the salivary flow rate). Dry mouth in cancer patients may lead to functional defects (e.g., eating, speaking, and swallowing), increase the risk of dental caries and oral candidiasis, and can have a negative effect on the nutritional and psychological status of the patients. The aim of this mini review was to summarize the current criteria for diagnosis and management of SGD associated with cancer treatment.

Oral Health Management and Rehabilitation for Patients with Oral Cancer: A Narrative Review

Surgery is the current first choice for oral cancer treatment. Intensity-modulated radiation therapy, molecular targeted drugs, and immune checkpoint inhibitors are still used as adjuvant therapy for advanced cancer. In addition, postoperative rehabilitation and multidisciplinary treatment have also been developed in recent years. Multidisciplinary team approaches and supportive care in oral cancer treatment reportedly shorten the time to treatment and improve outcomes. Although there is enough evidence confirming the role of oral and maxillofacial surgeons, dentists, and dental hygienists in supportive care in oral cancer treatment, there are very few systematic studies. In particular, oral health management is a concept that encompasses oral function management, oral hygiene management, and oral care during oral cancer treatment. We provide a narrative review focusing on oral health management from a multidisciplinary and supportive care perspective, applicable in oral cancer treatment.

Dental Caries Postradiotherapy in Head and Neck Cancer

BACKGROUND

Treatment for head and neck cancer (HNC) such as radiotherapy (RT) can lead to numerous acute and chronic head and neck sequelae, including dental caries. The goal of the present study was to measure 2-y changes in dental caries after radiotherapy in patients with HNC and test risk factors for caries increment.

METHODS

Cancer and dental disease characteristics, demographics, and oral health practices were documented before and 6, 12, 18, and 24 mo after the start of RT for 572 adult patients with HNC. Patients were eligible if they were age 18 y or older, diagnosed with HNC, and planned to receive RT for treatment of HNC. Caries prevalence was measured as decayed, missing, and filled surfaces (DMFS). The association between change in DMFS and risk factors was evaluated using linear mixed models.

RESULTS

On average, DMFS increased from baseline to each follow-up visit: 6 mo, +1.11; 12 mo, +2.47; 18 mo, +3.43; and 24 mo, +4.29 (P < 0.0001). The increase in DMFS during follow-up was significantly smaller for the following patient characteristics: compliant with daily fluoride use (P = 0.0004) and daily oral hygiene (brushing twice daily and flossing daily; P = 0.015), dental insurance (P = 0.004), and greater than high school education (P = 0.001). DMFS change was not significantly associated with average or maximum RT dose to the parotids (P > 0.6) or salivary flow (P > 0.1). In the subset of patients who had salivary hypofunction at baseline (n = 164), lower salivary flow at follow-up visits was associated with increased DMFS.

CONCLUSION

Increased caries is a complication soon after RT in HNC. Fluoride, oral hygiene, dental insurance, and education level had the strongest association with caries increment after radiotherapy to the head and neck region. Thus, intensive oral hygiene measures, including fluoride and greater accessibility of dental care, may contribute to reducing the caries burden after RT in HNC.

KNOWLEDGE TRANSFER STATEMENT

The results of this study can be used by clinicians when deciding how to minimize oral complications related to cancer therapy for patients with head and neck cancer. Identification of modifiable factors (e.g., oral hygiene and prescription fluoride compliance) associated with increased caries risk can minimize radiation caries burden.

Dosimetric Comparison between Volumetric Modulated Arc Therapy (VMAT) and Intensity-Modulated Radiotherapy (IMRT) for Dental Structures of Head and Neck Cancer Patients

Background

This retrospective study aimed to evaluate the radiation dose delivered to dental structures in intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) without dental dose constraints, compare the dosimetry differences of dental structures between the two radiation techniques, and determine whether dental structures should be one of the organs at risk for IMRT and VMAT plans according to the dosimetric analysis.

Materials and Methods

A total of 138 head and neck cancer patients (nasopharyngeal, oral cavity, pharyngeal, hypopharynx, and larynx), who underwent IMRT (69 patients) or VMAT (69 patients) from March 2016 to March 2021 in our hospital, were included to assess the dosimetry difference between two radiotherapy techniques for dental structures.

Results

The radiation dose delivered by IMRT and the mean maximum doses delivered by VMAT to the maxillary teeth of nasopharyngeal cancer patients were significantly higher than the dose received by the mandibular teeth. In contrast, the mandibular teeth of oral cavity cancer, oropharynx cancer, and laryngeal cancer received higher radiation doses than maxillary teeth. Except for mandibular teeth of oral cancer patients, the molars received significantly high-dose radiation than premolars and/or incisors in both radiotherapy techniques. No significant difference was observed between IMRT and VMAT in the dosimetric comparison of dental structures, except that oral cavity cancer patients treated with VMAT received a significantly higher mean average dose than those treated with IMRT. When PTV included level Ib, the radiation doses of the mandibular teeth delivered by both radiotherapy techniques were significantly higher than that in PTV when level Ib was excluded.

Conclusion

Without dental dose constraints, no major difference was observed between IMRT and VMAT plans in tooth dose distribution. We suggest that dental structures should be delineated as part of the organ at risk (OAR) when IMRT and VMAT are planned. Meanwhile, attention should be paid to dental structures that might have a high-dose area according to the specific tumor location.

Effect of Preirradiation Fluoride Treatment on the Physical Properties of Dentin

Objective. To determine the effects of preirradiation fluoride treatments on the Knoop hardness of dentin. Materials and Methods. Human posterior teeth mounted into acrylic resin molds were polished with silicon carbide (SiC) abrasives and 3-micron diamond paste. The Knoop hardness of dentin was measured with a Leco hardness instrument. The teeth were divided into groups of ten teeth per group as follows: no treatment (control), treatment with silver diamine fluoride (SDF), MI varnish (MI), and cavity shield (CS). The teeth were exposed to 2 Gy of daily radiation for six weeks using an X-Rad 320ix biological irradiator. Hardness was measured weekly, before, during, and after irradiation. The teeth were stored in artificial saliva at 37oC between radiation treatments. Results. In preirradiation dentin, a Knoop hardness value of 58.8 (14.1) KHN was obtained. Treatment with SDF significantly increased KHN before irradiation. Immediately after radiation treatment, hardness was significantly reduced in all experimental groups. Postirradiation fluoride treatments increased the hardness of dentin to varying degrees. Conclusions. Preirradiation fluoride treatment does not provide protection from decreases in the hardness of dentin. Treatment of teeth with fluoride formulations after radiation progressively restores the hardness of dentin to different degrees.

Pretreatment Systemic Immune-Inflammation Index Predict Needs for Teeth Extractions for Locally Advanced Head and Neck Cancer Patients Undergoing Concurrent Chemoradiotherapy

BACKGROUND

To evaluate the utility of pretreatment systemic immune-inflammation index (SII) in predicting the teeth caries and need for tooth extraction after concurrent chemoradiotherapy (C-CRT) for locally advanced squamous-cell head and neck cancer (LA-SCHNC) patients.

METHODS

The records of LA-SCHNC patients who underwent formal dental evaluations at pre- and post-C-CRT periods were retrospectively analyzed. The pretreatment SII values were calculated using the platelet, neutrophil, and lymphocyte measures acquired on the first day of C-CRT: SII=Platelets×neutrophils/lymphocytes. Receiver operating characteristic (ROC) curve analysis was employed to identify the ideal pre-C-CRT SII cutoff that may predict the teeth caries and the need for tooth extraction after the C-CRT. The primary endpoint was the link between the pre-C-CRT SII and the need for tooth extraction during the follow-up period.

RESULTS

A sum of 126 patients were included. Median follow-up was 4.9 years (range: 2.7-7.8). Nasopharyngeal and laryngeal cancers comprised the majority (75.4%) study cohort. Post-treatment teeth extractions were reported in 62.7% patients. The optimal cutoff was 558 [Area under the curve (AUC): %76.8 sensitivity: 72.3%; and specificity: 70.9%] that grouped the patients into two subgroups with significantly different post-C-CRT tooth extraction rates: Group 1: SII≤558 (n = 70) and SII>558 (n = 56), respectively. Correlation analysis revealed a significant relationship between the pretreatment SII and the tooth extraction rates after the C-CRT (rs:0.89: P = 0.001). The comparative analysis displayed that the teeth extractions rates were significantly higher in the SII>558 group (77.1% versus 51.4% for SII≤558; Hazard ratio: 1.68; P = 0.001). Further analyses showed that the pre-C-CRT SII>558 was the unique factor associated with meaningfully higher necessities for post-C-CRT teeth extractions.

CONCLUSION

The present outcomes intimated that high pretreatment SII levels were linked to significantly increased post-treatment teeth extractions in LA-SCHNC patients undergoing definitive C-CRT.

Prediction of Radiation-Related Dental Caries Through PyRadiomics Features and Artificial Neural Network on Panoramic Radiography

The prediction and detection of radiation-related caries (RRC) are crucial to manage the side effects of the head and the neck cancer (HNC) radiotherapy (RT). Despite the demands for the prediction of RRC, no study proposes and evaluates a prediction method. This study introduces a method based on artificial intelligence neural network to predict and detect either regular caries or RRC in HNC patients under RT using features extracted from panoramic radiograph. We selected fifteen HNC patients (13 men and 2 women) to analyze, retrospectively, their panoramic dental images, including 420 teeth. Two dentists manually labeled the teeth to separate healthy and teeth with either type caries. They also labeled the teeth by resistant and vulnerable, as predictive labels telling about RT aftermath caries. We extracted 105 statistical/morphological image features of the teeth using PyRadiomics. Then, we used an artificial neural network classifier (ANN), firstly, to select the best features (using maximum weights) and then label the teeth: in caries and non-caries while detecting RRC, and resistant and vulnerable while predicting RRC. To evaluate the method, we calculated the confusion matrix, receiver operating characteristic (ROC), and area under curve (AUC), as well as a comparison with recent methods. The proposed method showed a sensibility to detect RRC of 98.8% (AUC = 0.9869) and to predict RRC achieved 99.2% (AUC = 0.9886). The proposed method to predict and detect RRC using neural network and PyRadiomics features showed a reliable accuracy able to perform before starting RT to decrease the side effects on susceptible teeth.

Awareness of the risk of radiation-related caries in patients with head and neck cancer: A survey of physicians, dentists, and patients

OBJECTIVES

Radiation-related caries (RRC) is one of the most aggressive complications of radiotherapy (RT) in survivors of head and neck cancer (HNC). Lack of RRC awareness may contribute to the occurrence of this oral cavity complication. RRC may be considered a "forgotten oral complication" by patients with HNC, oncologists, and dentists. The present study aimed to assess the level of awareness of RRC among physicians, dentists, and patients.

STUDY DESIGN

Physicians (group 1, G1), dentists (group 2, G2), and patients with HNC undergoing RT (group 3, G3) answered questionnaires concerning their awareness of RRC. Physicians (G1) were divided into group 1A (oncological experience) and group 1B (general physicians/other specialties). Dentists (G2) were divided into group 2A (oncological experience) and group 2B (general dentists/other specialties). Personalized questionnaires were designed for each group.

RESULTS

Recruitment was as follows: physicians (n = 124): 1A (n = 64), 1B (n = 60); dentists: (n = 280), 2A (n = 160), 2B (n = 120). In addition, 58 patients answered the questionnaire. In terms of RRC awareness, 46.77% of physicians, 81.78% of dentists, and 24.13% of patients had some knowledge of the problem.

CONCLUSION

Patient awareness of RRC was poor. The heterogeneity of answers among physicians and dentists suggests an opportunity to improve patient education and prevention of this serious oral complication of RT.

Oral pH value predicts the incidence of radiotherapy related caries in nasopharyngeal carcinoma patients

Radiotherapy-related caries is a complication of radiotherapy for nasopharyngeal carcinoma; however, factors influencing the occurrence, accurate prediction of onset, and protective factors of radiotherapy-related caries remain unclear. This study analyzed risk factors, disease predictors, and protective factors for radiotherapy-related caries in nasopharyngeal carcinoma. This prospective study included 138 nasopharyngeal carcinoma patients receiving radical radiotherapy at our hospital during June 2012–December 2016 and were followed up for dental caries. Patients’ clinical data on radiotherapy were collected, dynamic monitoring was performed to assess changes in oral pH values, and a questionnaire survey was administered to collect patients’ lifestyle habits. Time-dependent cox regression trees, event-free Kaplan–Meier curve, Mann–Whitely U test were used to analysis the results. The median follow-up time was 30 (12–60) months. Radiotherapy-related caries occurred in 28 cases (20.3%). Univariate analyses showed that radiotherapy-related caries was associated with patient’s age, oral saliva pH value, green tea consumption, and radiation dose to sublingual glands, but not with the radiation dose to the parotid and submandibular glands. Multivariate analysis showed that oral saliva pH value [hazard ratio (HR) = 0.390, 95% confidence interval = 0.204–0.746] was an independent prognostic factor for radiotherapy-related caries. Patients with oral saliva pH values ≤ 5.3 in the 9th month after radiotherapy represented a significantly higher risks for radiotherapy-related caries (p < 0.001). Green tea consumption was associated with the occurrence of radiotherapy-related caries, and oral saliva pH values could predict the occurrence of radiotherapy-related caries. Limiting radiation doses to sublingual glands can reduce the occurrence of radiotherapy-related caries.

Conformational and constitutional analysis of dental caries following radiotherapy for head and neck cancer

Background

This study aimed to investigate the morphology and chemical composition of dental caries related to ionizing radiation (DCIR), an aggressive and progressive disease that affects dental hard tissues.

Materials and methods

Eight human teeth with DCIR were paired with sixteen control teeth (8 teeth with conventional caries and 8 without caries) and included in this study. An analysis of the morphology of the lesions was performed using the following techniques: periapical radiography, cone beam computed tomography, computed microtomography, and scanning electron microscopy. The chemical composition was assessed using X-ray dispersive spectroscopy.

Results

There was more demineralization in DCIR lesions when compared to conventional dental caries, even though there was no cavitation in the cervical region of the teeth. The superficial roughness and topography of DCIR lesions were similar to those of healthy teeth. On the other hand, lesions of conventional dental caries showed greater surface and topographic irregularity when compared to DCIR and healthy teeth (p = 0.001). Calcium (Ca) and phosphorus (P) levels were lower in DCIR lesions when compared to controls. However, higher levels of carbon (C) have been observed in DCIR lesions. There was a greater loss of the mineral matrix in DCIR followed by conventional caries. The reduction in the mineral matrix (Ca and P) was compatible with the imaging patterns observed in teeth with DCIR and conventional caries.

Conclusion

Despite their rapid evolution, DCIR presents an irregular, apparently intact surface with significant changes in the amount of Ca, P, and C.

Is there difference in the comparative and quantitative salivary proteome between stimulated and unstimulated saliva in head and neck cancer patients treated by radiotherapy?

Stimulation of saliva production is an alternative to improve the quality of life of patients treated by radiotherapy. However, there is no information about changes in the salivary proteome of stimulated and unstimulated saliva in these patients.

OBJECTIVES

Thus, we evaluated the difference in the proteomic profile of stimulated and unstimulated saliva in patients with head and neck cancer (HNC) treated by radiotherapy.

METHODS

Stimulated and unstimulated saliva were collected from 9 patients with HNC before (BRT), during (DRT; 2-5 weeks) and after (ART; 3-4 months) treatment. Healthy patients paired by age and gender also had their saliva collected (C; control group). The stimulated and unstimulated salivary flow were evaluated (p < 0.05). Salivary proteins were extracted and processed for shotgun proteomic analysis.

RESULTS

Significant differences were observed between stimulated and unstimulated salivary flows for C and BRT (p greater than 0.001), but not for DRT and ART. Proteins involved with apoptosis, antibacterial and acid-resistance were decreased in stimulated saliva in comparison to unstimulated saliva DRT and ART. Isoforms of keratins were not identified in control and BRT.

CONCLUSION

there is a marked difference in the protein profile of stimulated and unstimulated salivary flows in HNC patients treated by radiotherapy. In addition, saliva stimulation in patients with HNC decreases important proteins involved with dental protection. The unstimulated salivary flow seems to be the best alternative to search for biomarkers. Our results contribute in an unprecedented way to understand the changes in the salivary proteome of different flows in HNC patients undergoing radiotherapy treatment.

The effect of comprehensive oral care program on oral health and quality of life in patients undergoing radiotherapy for head and neck cancer: A quasi-experimental case-control study

OBJECTIVES

The purpose of this study is to investigate the effect of the comprehensive oral care program on oral health status and symptoms in head and neck cancer (HNC) patients undergoing radiotherapy.

METHODS

This was a quasi-experimental study using a non-equivalent control group in non-synchronized design. All participants including control and experimental group were asked for the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire H&N35 (EORTC QLQ-H&N35) and given an oral health education 4 times at baseline, immediate postradiotherapy, 3 months after radiotherapy, and 6 months after radiotherapy. In each visit except for final, the experimental group was given fluoride varnish application and fluoride mouth rinsing solution for daily use. Oral health examination for dental caries, plaque score (PS), bleeding on probing (BOP), and salivary flow rate was performed in baseline and 6 months after radiotherapy. Statistical analyses were done by paired t-tests and mixed ANCOVA repeated-measures analysis.

RESULTS

From November 1, 2013 to October 31, 2015, a total 61 patients undergoing radiotherapy for HNC cancer were enrolled (30 in control and 31 in experimental groups). Decrease in salivary flow rate was comparable between 2 groups. Dental caries increased in control group (P = .006); PS and BOP were decreased in experimental group (P < .001 and .004, respectively). Experimental group showed lower swallowing, speech problems, and less sexuality scores in EORTC QLQ-H&N35 than control group.

CONCLUSION

We found improvement in oral health and the quality of life in HNC patients with comprehensive oral care intervention by dental professionals. Communicating and cooperating between the healthcare and dental professionals is needed to raise the quality of health care services for HNC patients receiving radiotherapy.

Effect of ionizing radiation and cariogenic biofilm challenge on root-dentin caries

OBJECTIVES

To evaluate the effect of ionizing radiation and cariogenic biofilm challenge using two continuous flow models, normal and reduced salivary flow, on the development of initial root-dentin caries lesions.

MATERIALS AND METHODS

Microcosm biofilms were grown under two salivary flow rates (0.06 and 0.03 mL min^-1) and exposed to 5% sucrose (3 × daily, 0.25 mL min^-1, 6 min) dripped over non-irradiated and irradiated root-dentin blocks for up to 7 days. The vibration modes of root dentin, matrix/mineral (M/M), and carbonate/mineral (C/M) ratios were evaluated by FTIR. The mineral density was assessed by micro-CT.

RESULTS

With normal salivary flow, FTIR revealed an increase in the organic matrix (amide III) and a decrease in the mineral phase (ν_4, ν₂ PO₄^3-, AII + ν₂ CO₃^2-, C/M) in caries lesions. Irradiated dentin exhibited a reduction in the mineral phase (ν₁, ν₃ PO₄^3-, ν₂ CO₃^2-, C/M). Differences in mineral densities were not significant. With reduced salivary flow, FTIR also revealed increased organic matrix (amide III) for irradiated caries lesions and decrease in mineral phase (v_4, v₂ PO₄^3-, v₂ CO₃^2-, and C/M) in caries lesions. ν₁, ν₃ PO₄^3- precipitated on the surface of irradiated dentin and a lower mineral density was observed.

CONCLUSIONS

Initial caries lesions differed between non-irradiated and irradiated dentin and between normal and reduced salivary flow rates. Significant mineral loss with exposure of the organic matrix and low mineral density were observed for irradiated dentin with a reduced salivary flow rate.

CLINICAL RELEVANCE

Ionizing radiation associated with a reduced salivary flow rate enhanced the progression of root-dentin caries.

Protective effect of titanium tetrafluoride and silver diamine fluoride on radiation-induced dentin caries in vitro

This in vitro study evaluated the protective effect of titanium tetrafluoride (TiF₄) varnish and silver diamine fluoride (SDF) solution on the radiation-induced dentin caries. Bovine root dentin samples were irradiated (70 Gy) and treated as follows: (6 h): 4% TiF₄ varnish; 5.42% NaF varnish; 30% SDF solution; placebo varnish; or untreated (negative control). Microcosm biofilm was produced from human dental biofilm (from patients with head-neck cancer) mixed with McBain saliva for the first 8 h. After 16 h and from day 2 to day 5, McBain saliva (0.2% sucrose) was replaced daily (37 °C, 5% CO₂) (biological triplicate). Demineralization was quantified by transverse microradiography (TMR), while biofilm was analyzed by using viability, colony-forming units (CFU) counting and lactic acid production assays. The data were statistically analyzed by ANOVA (p < 0.05). TiF₄ and SDF were able to reduce mineral loss compared to placebo and the negative control. TiF₄ and SDF significantly reduced the biofilm viability compared to negative control. TiF₄ significantly reduced the CFU count of total microorganism, while only SDF affected total streptococci and mutans streptococci counts. The varnishes induced a reduction in lactic acid production compared to the negative control. TiF₄ and SDF may be good alternatives to control the development of radiation-induced dentin caries.

Occurrence and Treatment Outcome of Late Complications After Free Fibula Flap Reconstruction for Mandibular Osteoradionecrosis

PURPOSE

This study aimed to evaluate the occurrence and treatment outcome of late complications after free fibula osteocutaneous flap reconstruction for mandibular osteoradionecrosis (ORN).

METHODS

We enrolled 15 consecutive patients (14 men, one woman; median age 65 years, range 57-80 years) who underwent free fibula reconstruction for advanced mandibular ORN during 2013-2017 with two or more years of follow-up. Late complications included infection, plate exposure, and recurrence at the resection margin. The effect of perioperative antibiotic administration on late complications was also assessed.

RESULTS

Late complications occurred in 33.3% (5/15) of patients, including two infections (local and distant), two plate exposures, and two recurrences (plate exposure and recurrence occurred in one patient). Perioperative antibiotic administration duration did not significantly affect the occurrence of postoperative late complications. All late complications were treated without problems.

CONCLUSIONS

Late complications after ORN reconstructive surgery are not uncommon, but can be treated properly.

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.

Oral Implications of Polypharmacy in Older Adults

Over the next several decades, rates of aged populations will increase rapidly. These populations are susceptible to multimorbidities and polypharmacy (concurrently, prescribed 5 or more medications). Many medications have side effects that manifest orally. Therefore, it essential to possess current pharmacologic knowledge to diagnose and treat oral implications of commonly prescribed medications. This article details common medication-induced oral lesions and patient assessment of risk factors for polypharmacy and provides a template to integrate medication reconciliation into dental clinical practice.

Impact of non-compliance with oral care on radiation caries in head and neck cancer survivors

PURPOSE

A cross-sectional study was performed to quantify radiation caries (RC); explore the possible influence of various covariates like elapsed time since radiotherapy, cancer site and stage, treatment modality(ies), grades of xerostomia (GOX), and inter-incisal mouth opening on RC; and also to estimate the unmet treatment needs in head and neck cancer (HNC) survivors, where personal and professional oral care was neglected before and after completion of the treatment.

METHODOLOGY

Clinical status of the dentition was recorded using decayed missing filled surface/decayed missing filled teeth (DMFS/DMFT) index. Patients were grouped according to the respective covariates, and relevant statistical analysis was performed considering p value ≤ 0.05 as statistically significant.

RESULTS

Eighty nine patients, 72 males and 17 females, with a mean age of 52.37±11.19 (range 18-70) years were included in this study. Overall, 85% (76/89) and 78% (29/37), 87.5% (35/40), and 100% (12/12) of patients reporting within 1, 1-3, and 3-5 years after RT, respectively, were affected with RC. The mean DMFS/DMFT score, range, and standard deviation in the included patients up to 5 years post-RT were 61.12/15.99, 0-128/0-28, and 36.608/8.66, respectively. Unmet treatment needs concerning dental decay were 97%. A statistically significant difference was found between the mean DMFS with elapsed time since radiotherapy and different GOX, respectively.

CONCLUSION

Oral health will be worse, treatment needs will be high, and limitations to performing desirable treatment will be numerous in HNC patients, where the oral care component of their treatment is ignored. Future studies are required to identify the true relationship between various risk factors and the development and progression of RC.

Oral management strategies for radiotherapy of head and neck cancer

Radiotherapy, often with concomitant chemotherapy, has a significant role in the management of head and neck cancer, however, radiotherapy induces adverse events include oral mucositis, hyposalivation, loss of taste, dental caries, osteoradionecrosis, and trismus, all of which have an impact on patients' quality of life. Therefore, it is necessary to implement oral management strategies prior to the initiation of radiotherapy in patients with head and neck cancer. Since 2014, the National Comprehensive Cancer Network Clinical Practice Guidelines in Oncology (NCCN Guidelines) have enumerated the "Principles of Dental Evaluation and Management (DENT-A)" in the section on head and neck cancers, however, oral management was not explained in detail. Oral management has not been achieved a consensus protocol. The aim of this literature is to show that oral management strategy include removal infected teeth before the start of radiotherapy to prevent osteoradionecrosis, oral care for preventing severe oral mucositis to support patient complete radiotherapy during radiotherapy, and prevent of dental caries followed by osteoradionecrosis after radiotherapy.

Incidence of new carious lesions and tooth loss in head and neck cancer patients: a retrospective case series from a single unit

Introduction Radiation-induced xerostomia can result in increased caries incidence, necessitating more dental extractions and a resultant increased risk of debilitating osteoradionecrosis (ORN). Patients undergoing head and neck radiotherapy are routinely treated with a topical preventative regime consisting of fluoride and CPP-ACP (Tooth Mousse). There is limited evidence specifically relating to fluoride prevention regimes in head and neck cancer patients. Other novel remineralising aids using calcium and phosphate have been proposed for use in head and neck cancer patients, but again, there is limited evidence.Aims To retrospectively analyse head and neck cancer patients treated with radiotherapy and placed on a fluoride/CPP-ACP prevention regime at a single institution. To assess the incidence of caries, extractions and ORN.Materials and methods Case records for 95 patients were retrospectively assessed. This involved review of paper and computerised clinical notes, correspondence letters and radiographs.Results The mean number of carious teeth was 6.63 (SD 6.81) and the mean number of extractions was 4.88 (SD 5.84). The teeth most frequently affected by caries and extractions were the mandibular incisors, and 28.4% of patients developed ORN (81.5% of cases occurring in the mandible).Conclusion Development of caries and extraction was a very common event. There is a need for further research into the efficacy of topical prevention regimes.

The impact of timing and modalities of dental prophylaxis on the risk of 5-fluorouracil-related oral mucositis in patients with head and neck cancer: a nationwide population-based cohort study

PURPOSE

This study investigated the impact of dental prophylaxis on 5-fluorouracil (5-FU)-related oral mucositis (OM) according to the head and neck cancer (HNC) locations and treatment times.

METHODS

A total of 13,969 HNC participants, including 482 5-FU-related OM subjects and 13,487 comparisons were enrolled from the Longitudinal Health Insurance Database for Catastrophic Illness Patients of Taiwan between 2000 and 2008. All subjects were stratified into subgroups based on the times to perform chlorhexidine use, scaling, and fluoride application before 5-FU administration. The dental prophylaxis related to 5-FU-related OM was estimated by multiple logistic regression and represented with odds ratio (OR) and 95% confidence interval (CI).

RESULTS

Fluoride gel application and scaling significantly impacted on OM development (p < 0.001), and the joint effect of fluoride gel and scaling induced 5-FU-related OM (OR = 3.46, 95% CI = 2.39-5.01). The risk of OM was raised 2.25-fold as scaling within 3 weeks before 5-FU-related chemotherapy (95% CI = 1.81-2.81), and a 3.22-fold increased risk of OM while fluoride gel was applied during 5-FU-related treatment (95% CI = 1.46-7.13).

CONCLUSION

Dental prophylaxis significantly affected 5-FU-related OM in the HNC population. A short interval between dental scaling or fluoride application and 5-FU administration may be associated with higher prevalence of OM. Scaling simultaneously combined with chlorohexidine promoted 5-FU-related OM in specific HNC patients excluding the oral cancer and nasopharyngeal cancer population. Proper timing of the prophylactic dental treatments prior to 5-FU therapy could reduce the risk to develop 5-FU-related OM.

Squamous cell carcinoma of head and neck: what internists should know

Squamous cell carcinoma of head and neck (SCCHN) is a group of cancer arising from mucosal surfaces of the head and neck. Optimal management of SCCHN requires a multidisciplinary team of surgical oncologists, radiation oncologists, medical oncologists, nutritionist, and speech-language pathologists, due to the complexity of anatomical structure and importance of functional outcome. Human papilloma virus (HPV)-related SCCHN represents a distinct subset from HPV negative SCCHN which is associated with carcinogen exposure such as cigarette smoking, betel nut use and alcohol. HPV related SCCHN responds better to concurrent chemoradiation and has better overall prognosis, compared to HPV negative SCCHN. Radiation therapy has been introduced to the treatment of SCCHN, administered concurrently with systemic chemotherapy for locoregional SCCHN, as well as a palliative measure for recurrent and/or metastatic (R/M) SCCHN. Recently, immune checkpoint inhibitors have been shown to improve overall survival in R/M-SCCHN and have been incorporated into the standard of care. Combination approaches with immune therapy and targeted therapy for biomarker enriched population based on genomics are being actively investigated and will shape the future of SCCHN treatment.

In vivo and in vitro radiotherapy increased dentin enzymatic activity

OBJECTIVES

The present study investigated the effects of in vitro and in-vivo radiotherapy on endogenous enzymatic activity in dentin using gelatin zymography and in-situ zymography.

METHODS

Gelatin zymographic assays were performed on protein extracts obtained from dentin powder of sound non-irradiated (NRT), in vitro irradiated (VTRT) and in vivo irradiated (VIRT) human teeth. Their proteolytic activities were quantified using band densitometric evaluation. For in-situ zymography, dentin specimens from NRT, VIRT and VTRT were covered with fluorescein-conjugated gelatin and examined with confocal laser-scanning microscopy. Fluorescence intensity emitted by the hydrolyzed fluorescein-conjugated gelatin was quantified and statistically analyzed. In-situ zymography data were statistically analyzed using Kruskal-Wallis ANOVA and Dunn's multiple comparison procedures (α = 0.05).

RESULTS

No difference between in vitro and in vivo radiotherapy treatment was found. Both VTRT and VIRT groups showed increase in MMP-9 expression when compared to NRT group. Significant increases (p < 0.05) in gelatinolytic activity (26 % for VTRT; 55 % for VIRT) were observed when compared to the NRT group.

CONCLUSION

Radiotherapy increase endogenous enzymatic activity in non-restored dentin.

Head and Neck Cancers, Version 2.2020, NCCN Clinical Practice Guidelines in Oncology

Treatment is complex for patients with head and neck (H&N) cancers with specific site of disease, stage, and pathologic findings guiding treatment decision-making. Treatment planning for H&N cancers involves a multidisciplinary team of experts. This article describes supportive care recommendations in the NCCN Guidelines for Head and Neck Cancers, as well as the rationale supporting a new section on imaging recommendations for patients with H&N cancers. This article also describes updates to treatment recommendations for patients with very advanced H&N cancers and salivary gland tumors, specifically systemic therapy recommendations.

The DMFS160: A new index for measuring post-radiation caries

The current systems used to measure post-radiation caries underestimate the severity of the disease by failing to account for the unique spread of post-radiation caries, including incisal-edge and cusp tip decay, enamel delamination and crown amputation. A novel and clinically applicable index to measure post-radiation caries is proposed. The DMFS160 index counts 5 surfaces per tooth, accounting for incisal-edge caries, and is broken down into missing surfaces and decayed/filled surfaces. A staging and grading system is used to capture enamel delamination and crown amputation. The staging and grading provides a clinically-relevant measure at the whole-mouth level and is paired with evidence-based treatment strategies. In this paper the DMFS160 index is applied to three cases and compared to the DMFS index, demonstrating the improved accuracy of the DMFS160 index in measuring the extent of post-radiation caries.

Clinical and sociodemographic factors associated with oral health-related quality of life in survivors of head and neck cancer

BACKGROUND

Factors related to head and neck cancer and the treatment of the disease can affect quality of life. The aim of this study was to determine factors associated with the severity of impact on oral health-related quality of life (OHRQoL) in survivors of head and neck cancer using a multivariate analysis.

METHODS

This cross-sectional study evaluated 90 volunteers who had completed radiotherapy at least 3 months earlier. OHRQoL was assessed using oral health impact profile (OHIP-14) and the data were analyzed using robust variance poisson regression models.

RESULTS

The mean total OHIP-14 score was 23.98 ± 12.55. Patients with hyposalivation had 56% higher (worse) mean OHIP-14 total scores (CI:1.11-2.18) and patients with advanced stage tumors had 31% higher mean OHIP-14 total scores (CI:1.03-1.66) in multivariate analyses.

CONCLUSION

OHRQoL of survivors of head and neck cancer experienced a negative impact following radiotherapy. The impact was associated with hyposalivation and advanced stage tumors.

The impact of head and neck radiotherapy on the dentine-enamel junction: a systematic review

Background

Radiotherapy is widely used in contemporary head and neck cancer treatment protocols. The ability of head and neck radiotherapy (HNRT) to cause direct radiogenic destruction to the teeth is one of the most controversial topics in the field of oral oncology. Therefore, this systematic review aimed to investigate ionising radiation as an independent factor for physical and chemical changes on the dentine-enamel junction (DEJ), a pivotal dental topography for the onset and progression of radiation-related caries (RRC) and enamel delamination.

Material and Methods

Systematic searches were conducted on three databases: Scopus, MEDLINE (Via PubMed) and Embase (Elsevier). Laboratory studies evaluating the effects of simulated or in vivo HNRT on the DEJ were included. The GRADE tool adapted for in vitro studies was used to assess the methodological quality.

Results

Of the 154 initially selected studies, eight met the inclusion criteria, from which five studies were graded as high quality of evidence, two studies were graded as moderate quality and one as low quality. Two studies did not demonstrate DEJ alterations following HNRT while the other six articles described several organic and inorganic changes in the DEJ of irradiated teeth samples. These radiogenic events were mostly detected through micro and nanoindentation, Raman micro-spectroscopy, confocal microscopy, Western blotting and optical coherence tomography.

Conclusions

HNRT may have a negative impact on the physical and chemical aspects of the DEJ, predisposing cancer patients to RRC and enamel delamination.

Key words:Cancer, radiotherapy, radiation-related caries, dentin-enamel junction, systematic review.

Change of saliva composition with radiotherapy

OBJECTIVE

The aim of this study was to analyze the physiological and microbiological changes of saliva from patients with head and neck cancer during and after intensity-modulated radiotherapy (IMRT).

DESIGN

In this prospective clinical trial saliva samples and oral candida swabs were collected from patients receiving IMRT due to head and neck cancer (examination group). The first measurement was scheduled before radiotherapy, the other measurements during and after radiotherapy up to a one year follow-up. Additionally samples from healthy controls were collected over six weeks. Salivary flow rate and pH were measured. Microbiological analysis of cariogenic and periodontopathogenic taxa was performed by fluorescence in situ hybridization and oral Candida spp occurrence was evaluated by swab tests.

RESULTS

11 patients and 19 controls were included. The salivary flow rate and the unstimulated pH of the examination group were significantly reduced during radiotherapy compared with the measurement before radiotherapy and to the control group. Total bacteria, streptococci and lactobacilli numbers slightly increased after radiotherapy, resuming baseline levels after one year. Mutans streptococci, Porphyromonas gingivalis and Treponema denticola were barely detectable, whereas Tannerella forsythia slightly increased following radiotherapy. No differences in Candida levels were observed in the study.

CONCLUSIONS

Salivary changes in quantitative, qualitative and microbial composition occur during and after radiotherapy, with resumption of the measurements towards baseline levels after one year. While low levels of cariogenic and periodontopathogenic species were detected, the lower pH and salivary flow combined with increased numbers of aciduric and acidogenic lactobacilli corroborates a higher risk for caries, necessitating prevention.

Algorithmic analysis for dental caries detection using an adaptive neural network architecture

Objectives

AI techniques have lifelong impact in biomedics and widely accepted outcomes. The sole objective of the study is to evaluate accurate detection of caries using feature extraction and classification of the dental images along with amalgamation Adaptive Dragonfly algorithm (DA) algorithm and Neural Network (NN) classifier.

Materials and methods

Here proposed caries detection model is designed for detecting the tooth cavities in an accurate manner. This methodology has two main phases; feature extraction and classification. In all total 120 images database is split into three sets, randomly for evaluating the performance. Further, this categorization of the test cases aids in ensuring the enhancement of the performance. In each of the test cases, there are 40 caries images the investigation in the performance of the proposed caries detection model was done in terms of accuracy, sensitivity, specificity, and precision, FPR, FNR, NPV, FDR, F1Score and MCC.

Results

Here MPCA with Nonlinear Programming and Adaptive DA, the proposed model is termed as MNP-ADA. The performance of the proposed MPCA-ADA model is evaluated by comparing it over the other existing feature extraction models. MPCA–ADA over the conventional classifier models like PCA-ADA, LDA-ADA and ICA-ADA in terms of performance parameters and MCC for all the test types and have superior results than the existing ones.

Conclusion

The research work emphasizes the prospective efficacy of IP and NN algorithms for the detection and diagnosis of dental caries. A novel and improved model shows substantially worthy performance in distinguishing dental caries using image processing techniques.

Dentin-pulp complex reactions in conventional and radiation-related caries: A comparative study

Background

Radiation-related caries (RRC) is one of the most significant oral toxicities of head and neck radiotherapy (HNRT); however, the potential of radiation to directly cause harmful dentin and pulpal effects and impair response to caries progression is controversial.

Material and Methods

Therefore, the aim of this study was to characterize the reactions of the dentin-pulp complex in teeth affected by RRC. Patients and methods: Twenty-two carious teeth extracted from 22 head and neck cancer (HNC) patients were divided into control (conventional caries; n=11) and irradiated (RRC; n=11) groups and paired matched by dental homology, clinical patterns of caries progression following the Post-Radiation Dental Index (PRDI) and microscopic depth of carious invasion. Histopathological characteristics based on morphological hierarchy, cell populations of dental pulp, blood vessels, neural elements, extracellular matrix components, inflammation, patterns of carious invasion and reactionary dentin presence were evaluated by optical light microscopy and histomorphometry.

Results

Mean PRDI scores were 3.2 for the control group and 3.8 for the irradiated group. Dentin demineralization patterns were also similar between the groups and the mean depths of demineralization were 1,158.58µm and 1,056.89µm for the control and irradiated groups, respectively.

Conclusions

Pulp histopathological changes and dentin reaction patterns were similar between groups and varied according to the PRDI scores and carious lesions depth. Dentin and pulp reactions are highly preserved in RRC teeth. Key words:Cancer, radiotherapy, radiation-related caries, teeth, pulp.