Radiation-related damage to dentition

Ultrasonic activation of adhesive systems increases bond strength and intratubular penetration of resin cement in root dentin subjected to radiation therapy

OBJECTIVE

This study aimed to evaluate the effect of ultrasonic activation of etch-and-rinse and self-etch adhesive systems on the bond strength of resin cement to irradiated root dentin.

MATERIALS AND METHODS

Eighty human maxillary anterior teeth were distributed into 8 groups (n = 10), according to the type of adhesive system used (etch-and-rinse and self-etch), the ultrasonic activation of the adhesive systems, and the dentin condition (irradiated or non-irradiated - 70 Gy). Endodontic treatment was performed followed by fiberglass post-space preparation. After fiberglass posts' luting, the roots were transversely sectioned on dentin discs and submitted to the push-out bond strength test (0.5 mm/min). The fractured specimens were analyzed under a stereomicroscope and Scanning Electron Microscope (SEM) for failure mode classification. One of the dentin discs was analyzed under SEM to evaluate the characteristics of the adhesive interface.

RESULTS

Irradiated specimens had lower bond strength than non-irradiated specimens (P < 0.0001). Ultrasonic activation of both adhesive systems increased the bond strength of the resin cement to irradiated dentin (P < 0.0001). Radiotherapy significantly affected the failure mode in the middle (P = 0.024) and apical thirds (P = 0.032) (adhesive failure).

CONCLUSION

Non-irradiated specimens had a more homogeneous adhesive interface. When ultrasonically activated, both adhesive systems showed a greater number of resinous tags, regardless of the dentin condition.

CLINICAL RELEVANCE

Ultrasonic activation of adhesive systems is a feasible strategy to enhance fiberglass posts retention in oncological patients.

Dentist Involvement in the Treatment of Radiation-Induced Oral Mucositis-A Pilot Cross-Sectional Study

Objectives: Oral mucositis (OM) occurs in more than 95% of patients irradiated in the head and neck area. This paper aims to determine the occurrence and characteristics of OM in patients with head and neck cancer (HNC), as well as the involvement of dentists/oral medicine specialists in treating such patients. Methods: This study was conducted at the Department of Otorhinolaryngology and Department of Oral Medicine, University Hospital Center Zagreb, from April to August 2022, on patients irradiated in the head and neck area. A unique OM questionnaire was created on the incidence, characteristics, oral care, and involvement of dentists in the overall care. Results: Thirty patients filled out the questionnaire. Of the 22 patients who had developed OM, 14 had grade-three OM. Ten patients were treated for OM in line with the instructions of an oral medicine specialist, eight based on the instructions of a specialist responsible for monitoring of the underlying disease, and four were not treated at all. Sixteen patients had not been referred to a dentist before the start of RT. Conclusions: These results showed insufficient care and treatment of OM, as well as insufficient involvement of dentists in the oncology team.

Prevalence of acute periapical abscesses in head and neck cancer patients receiving radiotherapy

AIMS

Head and neck cancer is a serious condition affecting the life of patients. Radiotherapy is commonly used to treat such conditions. The aim of this study was to assess the prevalence of acute periapical abscesses (PAs) in patients who received radiotherapy for head and neck cancer.

METHODS AND RESULTS

Data on acute PAs and oropharyngeal cancer (OPC) diagnosis with or without a history of radiation therapy (RAD) was retrieved by searching the appropriate query in the database. All cases were diagnosed for acute PAs by calibrated dentists for patients admitted to urgent care. The odds ratio (OR) for the prevalence of acute PAs and its association with a history of OPC with or without RAD were then calculated. Adjustment for comorbidities such as diabetes, smoking and gingival and periodontal diseases was also done. The prevalence of acute PAs in patients with a history of OPC was significantly higher as compared to the general hospital patient population (OR 2.92, 95%CI, p < .0001). Males were more affected than females and whites were more affected than African Americans and other ethnicities. The prevalence for PAs in patients with a history of OPC and RAD was higher and the difference in prevalence was statistically significant (OR 3.61, 95%CI, p < .0001). Whites were more affected than African Americans by more than 3.5-fold. Adjustment for diabetes comorbidly affected mainly the OPC + RAD group, however, the difference remained statistically significant. Adjustment for smoking and gingival and periodontal disease reduced the OR but the difference remained statistically different.

CONCLUSIONS

The high prevalence of acute PAs in patients with a history of OPC and RAD may suggest an association between these conditions warranting a meticulous medical and dental examination.

Interdisciplinary Collaboration in Head and Neck Cancer Care: Optimizing Oral Health Management for Patients Undergoing Radiation Therapy

Radiation therapy (RT) plays a crucial role in the treatment of head and neck cancers (HNCs). This paper emphasizes the importance of effective communication and collaboration between radiation oncologists and dental specialists in the HNC care pathway. It also provides an overview of the role of RT in HNC treatment and illustrates the interdisciplinary collaboration between these teams to optimize patient care, expedite treatment, and prevent post-treatment oral complications. The methods utilized include a thorough analysis of existing research articles, case reports, and clinical guidelines, with terms such as 'dental management', 'oral oncology', 'head and neck cancer', and 'radiotherapy' included for this review. The findings underscore the significance of the early involvement of dental specialists in the treatment planning phase to assess and prepare patients for RT, including strategies such as prophylactic tooth extraction to mitigate potential oral complications. Furthermore, post-treatment oral health follow-up and management by dental specialists are crucial in minimizing the incidence and severity of RT-induced oral sequelae. In conclusion, these proactive measures help minimize dental and oral complications before, during, and after treatment.

Oral Health in Patients with History of Head and Neck Cancer: Complexity and Benefits of a Targeted Oral Healthcare Pathway

PURPOSE OF REVIEW

This work consists in a literature review on the current state of knowledge regarding the oral management of patients with a history of head and neck cancer (HNC), corroborated by clinical cases and illustrated by clear infographic summaries. It aims to provide healthcare professionals with a comprehensive overview of the oral health status of HCN patients.

RECENT FINDINGS

Head and neck cancers (HNCs) represent the seventh most common type of cancer worldwide, with over 660,000 annual new cases. Despite the significant negative impact of HNCs on oral health, patients often receive no or inappropriate oral care while the significant impact of oral pathologies on cancer prognosis is commonly underestimated. This work (i) describes the oral cavity during and after HNC through the prism of care complexity and (ii) highlights several potential key factors that could worsen long-time patients' prognosis and quality of life. By investigating the biological, microbiological, functional, and psychological dimensions of the interrelationships between HNCs and oral health, the authors explored the barriers and benefits of a targeted oral healthcare pathway. This article emphasizes the importance of multidisciplinary care and highlights the need for further research elucidating the intricate relationships between oral health and HNCs, particularly through the microbiota.

The impact of radiation caries on morbidity and mortality outcomes of head and neck squamous cell carcinoma patients

AIMS

Radiation caries (RC) is a highly prevalent and chronic complication of head and neck radiotherapy (HNRT) and presents a challenge for clinicians and patients. The present study aimed to assess the impact of RC on the morbidity and mortality outcomes of head and neck squamous cell carcinoma (HNSCC) patients.

METHODS AND RESULTS

Patients were divided into three groups: (1) RC (n = 20), (2) control (n = 20), and (3) edentulous (n = 20). Information regarding the number of appointments, dental procedures, osteoradionecrosis (ORN), prescriptions, and hospital admissions were collected. Mortality outcomes were assessed through disease-free survival (DFS) and overall survival (OS) rates. RC patients required more dental appointments (p < .001), restorations (p < .001), extractions (p = .001), and antibiotic and analgesic prescriptions (p < .001). Kaplan-Meier subgroup analyses showed a significantly increased risk of ORN in RC compared to edentulous patients (p = .015). RC patients presented lower DFS rates (43.2 months) than the control and edentulous groups (55.4 and 56.1 months, respectively).

CONCLUSIONS

RC impacts morbidity outcomes among cancer survivors due to increased demand for medication prescriptions, multiple specialized dental appointments, invasive surgical treatments, increased risk of ORN, and increased need for hospital admissions.

Clinical efficacy of endodontic protocols on reducing cultivable bacteria and endotoxin in infected root canal in patients submitted to head and neck radiotherapy: a randomised clinical trial

OBJECTIVES

Assess the efficacy of biomechanical preparation using a reciprocating system followed by final irrigation protocols, then intracanal medication, on reducing endotoxins and cultivable bacteria of infected teeth in irradiated patients.

MATERIALS AND METHODS

Twenty-two infected single-rooted canals in patients submitted to head and neck radiotherapy were prepared by reciprocating motion and 2.5% NaOCl. Patients were randomly divided into two groups of 11 patients before the final irrigation protocol: apical positive pressure (APP) or passive ultrasonic activation (PUA). Both groups were treated in two sessions, using Ca(OH)2 as intracanal medication for 14 days. Root canal content sampling was performed after canal access (S1), after biomechanical preparation plus the irrigation protocol (S2), and after intracanal medication (S3). Chromogenic limulus amoebocyte lysate assay measured endotoxin levels (EU/mL), and bacterial load was determined by culture techniques (CFU/mL).

RESULTS

Treatment protocols reduced bacterial counts after S2 in both groups (p = 0.01). S3 differed from S1 (p = 0.01), but not from S2 (p = 0.4). Endotoxin levels were reduced in both groups after S2 (P = 0.03) and were lower in S3 than in S2, with significant differences in the APP group (p = 0.03).

CONCLUSIONS

Biomechanical preparation using a reciprocating system and 2.5% NaOCl in irradiated teeth, followed by the irrigation protocol (APP or PUA), demonstrated efficacy in reducing endodontic contaminants. Ca(OH)2 as intracanal medication should be performed in irradiated patients with infected root canals.

CLINICAL RELEVANCE

This clinical study demonstrated that endodontic treatment in irradiated patients is efficacious at reducing bacterial load and endotoxin levels.

Compliance with oral hygiene and dietary advice for the prevention of post-radiotherapy dental disease among head and neck cancer patients - a qualitative study

OBJECTIVES

To elicit head and neck cancer (HANC) patients' views about their oral health and to identify potential issues regarding compliance with clinical oral hygiene and dietary advice for the prevention of post-radiotherapy dental disease.

METHODS

A purposive sample of twelve HANC patients between 6- and 12-months post-radiotherapy were recruited to undergo a semi-structured interview with a qualitative researcher. A pre-piloted topic guide was used to frame each interview. Qualitative data were analysed via thematic analysis.

RESULTS

Data were categorised into four main themes - 'How HANC patients perceive oral health', 'Cancer diagnosis and cancer care pathway', 'Impact of oncology treatment (radiotherapy, surgery, and chemotherapy)', and 'Post-oncology treatment recovery', with 14 subthemes. Oral health was viewed as an important component of HANC patients' overall physical and mental health post-treatment. Patients' non-compliance with adequate oral hygiene practice was related to oral mucositis, a "burning" sensation associated with high fluoride toothpaste, forgotten or inconsistent clinical advice, and an inadequate supply of preventive oral hygiene products. The potentially highly cariogenic nature of prescribed nutritional supplements for patients at risk of malnutrition did not tend to be communicated to patients in advance of their prescription.

CONCLUSIONS

Adequate oral health is essential for the overall physical and mental well-being of post-treatment HANC patients. Non-compliance with preventive clinical advice increases the risk of post-treatment oral health deterioration and was related to miscommunication, inadequate supplies of oral hygiene products, and treatment-related oral discomfort.

CLINICAL SIGNIFICANCE

Post-treatment HANC patients are at increased risk of dental disease. Educational and behavioural techniques should be employed to enhance patients' compliance with clinical oral hygiene and dietary advice for the prevention of post-radiotherapy dental disease. Patients should be informed about the potentially highly cariogenic nature of nutritional supplements, and these patients should undergo frequent dental recall. Clinical advice regarding oral hygiene and dietary practices needs to be given consistently to HANC patients by different specialists of the HANC multidisciplinary team.

Accounting for fractionation and heterogeneous dose distributions in the modelling of osteoradionecrosis in oropharyngeal carcinoma treatment

BACKGROUND AND PURPOSE

Osteoradionecrosis (ORN) of the mandible is a severe complication following radiotherapy (RT). With a renewed interest in hypofractionation for head and neck radiotherapy, more information concerning ORN development after high fraction doses is important. The aim of this explorative study was to develop a model for ORN risk prediction applicable across different fractionation schemes using Equivalent Uniform Doses (EUD).

MATERIAL AND METHODS

We performed a retrospective cohort study in 334 oropharyngeal squamous cell carcinoma (OPSCC) patients treated with either a hypofractionated Stereotactic Body Radiation Therapy (HF-SBRT) boost or conventional Intensity Modulated Radiation Therapy (IMRT). ORN was scored with the CTCAE v5.0. HF-SBRT and IMRT dose distributions were converted into equivalent dose in 2 Gy fractions (α/β = 0.85 Gy) and analyzed using EUD. The parameter a that led to an EUD that best discriminated patients with and without grade ≥ 2 ORN was selected. Patient and treatment-related risk factors of ORN were analyzed with uni- and multivariable regression analysis.

RESULTS

A total of 32 patients (9.6%) developed ORN grade ≥ 2. An EUD(a = 8) best discriminated between ORN and non-ORN (AUC = 0.71). In multivariable regression, pre-RT extractions (SHR = 2.34; p = 0.012), mandibular volume (SHR = 1.04; p = 0.003), and the EUD(a = 8) (SHR = 1.14; p < 0.001) were significantly associated with ORN.

CONCLUSION

Risk models for ORN based on conventional DVH parameters cannot be directly applied to HF-SBRT fractionation schemes and dose distributions. However, after correcting for fractionation and non-uniform dose distributions using EUD, a single model can distinguish between ORN and non-ORN after conventionally fractionated radiotherapy and hypofractionated boost treatments.

Effects of systemic Anatolian propolis administration on a rat-irradiated osteoradionecrosis model

OBJECTIVE

Radiotherapy after head and neck cancer is associated with the risk of osteonecrosis development. This study aims to investigate the effectiveness of systemic propolis application to prevent the disease as it has no definite treatment protocol despite the proposed treatment methods and significantly decreases individuals' quality of life.

METHODOLOGY

In total, 29 male Wistar-Albino rats were divided into control, 35 Gy irradiation (Group 1), 35 Gy irradiation+100 mg/kg/ml propolis administration (Group 2), and 35 Gy irradiation+200 mg/kg/ml propolis administration groups (Group 3). Propolis was first applied on the day after radiotherapy, except for the control group. Right first and second molars were extracted from all rats three weeks following radiotherapy. Samples were collected seven weeks after radiotherapy. Osteoblast and osteoclast counts were calculated by histomorphometric analysis. Immunohistochemical analysis determined bone morphogenic protein-2 (BMP-2) and transforming growth factor beta-3 (TGFβ-3).

RESULTS

Group comparison found non-significant differences regarding osteoblast (p=0.130) and osteoclast (p=0.063) counts. However, Group 1 showed the lowest mean osteoblast (OBL: 82.63 [±13.10]) and highest mean osteoclast counts (OCL: 12.63 [±5.55]). OBL/OCL ratio showed significant differences between groups (p=0.011). Despite the significant difference between the Control and Groups 1 (p=0.006) and 2 (p=0.029), Group 3 showed a non-significant difference (p=0.091). For BMP-2 and TGFB3, the control group showed significant differences with the other two groups (p<0.001), except for Group 3.

CONCLUSION

Anatolian propolis showed beneficial effects in a radiotherapy-mediated osteonecrosis model, highlighting its potential as a promising intervention.

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.

Genetic markers associated with adverse reactions of radioiodine therapy in thyroid cancer patients

OBJECTIVES

Radioactive iodine therapy is considered for patients with certain clinicopathological factors that predict a significant risk of recurrence, distant metastases of thyroid cancer or disease-specific mortality. The aim of the study was to investigate the association between polymorphisms of genes, products of which are involved in the processes of DNA damage response and autophagy, and the adverse reactions of radioiodine therapy in thyroid cancer patients.

METHODS

The study included 181 patients (37 men, 144 women; median age 56 [41; 66.3] years) with histologically confirmed thyroid cancer and a history of thyroidectomy who received radioiodine therapy. NFKB1, ATM, ATG16L2, ATG10, TGFB1, and TNF polymorphisms were determined by allele-specific realtime-PCR.

RESULTS

The frequency of adverse reactions was the following: gastrointestinal symptoms - 57.9 %, local symptoms - 65.8 %, cerebral symptoms - 46.8 %, fatigue - 54.4 %; signs of sialoadenitis six months after radioiodine therapy - 25.2 %. TT genotype carriers of ATG10 rs1864183 had higher frequency of gastrointestinal symptoms (vs. CC+CT), the CC genotype carriers of ATG10 rs10514231 had significantly more frequent cerebral symptoms (vs. CT+TT), as well as AA genotype carriers of TGFB1 rs1800469 (vs. AG+GG). CC genotype of ATG10 rs10514231 increased the incidence of radioiodine-induced fatigue, whereas GA genotype of the ATM rs11212570 had a protective role against fatigue. TGFB1 rs1800469 was associated with signs of sialoadenitis six months after radioiodine therapy.

CONCLUSIONS

Genetic factors may contribute to the occurrence of adverse reactions of radioiodine therapy in thyroid cancer patients.

Ex-vivo analysis of demineralisation on irradiated teeth using optical coherence tomography

Head and neck cancer patients are prone to dental caries after radiotherapy. An ex-vivo study was conducted to assess the feasibility of optical coherence tomography (OCT) to detect tooth demineralization due to caries in irradiated teeth. Thirty-nine human molar teeth were subjected to caries lesion induction through irradiation (Group 1), pH cycling (Group 2-1), and both (Group 2-2). The OCT signal attenuation coefficient, µR was assessed and validated against microhardness test and scanning electron microscope (SEM). The µR for Group 1 increased from 10 Gy to 40 Gy, and subsequently decreased after irradiated to 50 Gy and 60 Gy due to damaged enamel microstructure. In Group 2-1, the µR decreased with duration of pH cycling from day 1 to day 14 due to the increase of porosity in enamel layer. However, the µR showed decreasing trend from day 14 to day 28 of pH cycling, resulted from mineral deposition in the enamel layer. Although no significant difference was found in the µR between Group 2-1 and 2-2, SEM of Group 2-2 demonstrated visually higher porosity and larger gaps between microstructures. Irradiation may accelerate caries damage to tooth microstructure by increasing its porosity and brittleness, but larger sample size may be needed to further prove the effect. OCT could potentially be used for early detection of tooth demineralization in vivo based on the measurable µR changes for all groups which are shown negatively correlated with microhardness value (p < 0.05).

Effect of Ionizing Radiation on the Mechanical Properties of Two Dental Materials Commonly Used in Primary Teeth

Aim

The purpose of this in vitro study was to evaluate the effect of radiotherapy on flexural strength, microhardness, and surface roughness of bulk fill composite (X-tra fil) and glass ionomer (EQUIA Forte HT).

Materials and methods

A total of 40 specimens were prepared for each test and were divided into two groups according to the material used (composite or glass ionomer cement), and each group was divided into two subgroups (n = 10) according to radiation condition, irradiated subgroup, subjected to 50 Gy by multienergy linear accelerator delivered in one shot and control subgroup.

Results

Control samples of flexural strength and microhardness had a significantly higher value than irradiated samples in both materials. Regarding the surface roughness, irradiated samples had a significantly higher value than the control samples in both materials.

Conclusion

Irradiation with a linear accelerator had a negative impact on the flexural strength and microhardness of both materials. Moreover, it increased the surface roughness for both materials. Bulk fill composite is the dental restorative material of choice in head and neck cancer patients undergoing radiotherapy due to its high mechanical properties before and after radiation.

How to cite this article

Nagi BM, El-Korashy DI, Amin A El-S, et al. Effect of Ionizing Radiation on the Mechanical Properties of Two Dental Materials Commonly Used in Primary Teeth. Int J Clin Pediatr Dent 2023;16(5):758-762.

Genetic markers associated with adverse reactions of radioiodine therapy in thyroid cancer patients

OBJECTIVES

Radioactive iodine therapy is considered for patients with certain clinicopathological factors that predict a significant risk of recurrence, distant metastases of thyroid cancer or disease-specific mortality. The aim of the study was to investigate the association between polymorphisms of genes, products of which are involved in the processes of DNA damage response and autophagy, and the adverse reactions of radioiodine therapy in thyroid cancer patients.

METHODS

The study included 181 patients (37 men, 144 women; median age 56 [41; 66.3] years) with histologically confirmed thyroid cancer and a history of thyroidectomy who received radioiodine therapy. NFKB1, ATM, ATG16L2, ATG10, TGFB1, and TNF polymorphisms were determined by allele-specific realtime-PCR.

RESULTS

The frequency of adverse reactions was the following: gastrointestinal symptoms - 57.9 %, local symptoms - 65.8 %, cerebral symptoms - 46.8 %, fatigue - 54.4 %; signs of sialoadenitis six months after radioiodine therapy - 25.2 %. TT genotype carriers of ATG10 rs1864183 had higher frequency of gastrointestinal symptoms (vs. CC+CT), the CC genotype carriers of ATG10 rs10514231 had significantly more frequent cerebral symptoms (vs. CT+TT), as well as AA genotype carriers of TGFB1 rs1800469 (vs. AG+GG). CC genotype of ATG10 rs10514231 increased the incidence of radioiodine-induced fatigue, whereas GA genotype of the ATM rs11212570 had a protective role against fatigue. TGFB1 rs1800469 was associated with signs of sialoadenitis six months after radioiodine therapy.

CONCLUSIONS

Genetic factors may contribute to the occurrence of adverse reactions of radioiodine therapy in thyroid cancer patients.

Effects of direct therapeutic radiation on pulpal surface of root dentin: an in vitro study

The aims of the study were to analyze the effects of therapeutic radiation on human root dentin samples from the aspect of possible alterations in crystallinity, micro-morphology, and composition. Fifty-six root dentin specimens were divided into seven groups (0, 10, 20, 30, 40, 50, and 60 Gy). Scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) analyses were performed on pulpal surfaces of root dentin after being irradiated by 6MV photon energy. Mineral compositions, Ca/P, P/N, Ca/N ratios, and hydroxyapatite pikes were calculated. Some deuteriations on the dentin surface were observed in SEM images after 30 Gy and subsequent doses. One-way ANOVA revealed that there was no significant alteration in weight percentages of C, O, Mg, Ca, P, and N between groups. Radiation did not influence stoichiometric Ca/P, Ca/N, and P/N molar ratios. XRD analysis did not show a remarkable decline in hydroxyapatite pikes by the increasing doses. Radiotherapy changes the micromorphology of circumpulpal dentin but does not affect elemental composition and crystallinity.

The Revived Interest in Ageusia Research during the COVID-19 Pandemic: A Bibliometric Analysis

The evolution of ageusia research literature has yet to be investigated. This bibliometric study analyzed the entire ageusia research literature indexed in Web of Science, to reveal its growth and the most productive entities in terms of authors, institutions, countries, journals, and journal categories. In addition, this study aimed to identify medical conditions (and their treatments) that were frequently associated with ageusia. On 7 March 2022, the Web of Science Core Collection database was accessed with the following search query: TS = (ageusia OR "taste loss" OR "loss of taste" OR "loss of gustat*" OR "gustatory loss"). The search identified publications mentioning these terms in their title, abstract, or keywords. No additional filters were placed on publication year, language, etc. The basic publication and citation counts were extracted from the in-built functions of the database. The complete record of the publications was exported into VOSviewer, a bibliometric software for visualizations. The search yielded 1170 publications. The cumulative publication and citation counts of the ageusia research sharply increased in 2020. The most productive author was Professor Thomas Hummel from Technische Universität Dresden. Ageusia research had heavy contributions from the United States, Italy, the United Kingdom, Germany, and India. The top 5 most productive journals mainly belonged to the otorhinolaryngology and medicine categories. The medical conditions frequently investigated in ageusia research included COVID-19, cancers (head and neck, and advanced basal cell), Guillain-Barré syndrome, neurodegenerative diseases, diabetes, and Sjogren's syndrome. This study could act as a begvinner's guide for (1) clinicians who are not familiar with ageusia so that they might better understand which scenarios they need to be more aware of since ageusia could be a co-morbidity of a patient's underlying disease, and (2) for those who wish to search for relevant authors and journals for suitable publications related to the topic.

Time-dependent structural changes and hypermineralisation of artificially demineralised dentine following treatment with silver diammine fluoride and glass ionomer cement

OBJECTIVES

This study aimed to evaluate the change of mineral content in dentine lesions over time and examine the effectiveness of the combined treatment with silver diammine fluoride (SDF) and glass ionomer cement (GIC).

METHODS

Sixty bovine dentine specimens were divided into 4 groups: cont, Fuji, Safo, and Safo+Fuji. The specimens were imaged and measured using microcomputed tomography (microCT) at 7 time points: pre-demineralisation, after demineralisation for two weeks, immediately after treatment, 1 week, 2 weeks, 1 month, and 3 months after treatment. The 3-month group was evaluated with a light microscope, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, and scanning electron microscope (SEM)/energy-dispersive X-ray spectroscopy (EDS). Data were analysed by Dunn's test and Wilcoxon signed rank test with Bonferroni correction for microCT, and Kruskal-Wallis test and two-way analysis of variance for EDS characterisation.

RESULTS

MicroCT images showed high mineral density beneath dentine lesions in Safo+Fuji. The mineral density at 600 μm in Safo+Fuji increased significantly over time, while Safo showed an opposite trend (adjusted p<0.005). In Safo+Fuji, EDS revealed significantly high energy of fluorine (p<0.05, at 300 μm) and a tendency towards high energy of calcium (p>0.05). However, Safo+Fuji showed lower energy of silver compared to Safo (p<0.001). ATR-FTIR revealed that phosphate groups had the highest peak at a depth between 300 and 400 μm in Safo+Fuji.

CONCLUSIONS

Safo+Fuji was effective in remineralising the deep lesion in dentine after one and three months, and a hypermineralisation zone generated beneath the lesion demonstrated additional benefit in this study.

CLINICAL SIGNIFICANCE

This long-term in vitro study showed that SDF+GIC treatment could strengthen the structure of decayed teeth when applied in the treatment of patients with advanced rampant caries.

Therapeutic benefits of factors derived from stem cells from human exfoliated deciduous teeth for radiation-induced mouse xerostomia

Radiation therapy for head and neck cancers is frequently associated with adverse effects on the surrounding normal tissue. Irreversible damage to radiation-sensitive acinar cells in the salivary gland (SG) causes severe radiation-induced xerostomia (RIX). Currently, there are no effective drugs for treating RIX. We investigated the efficacy of treatment with conditioned medium derived from stem cells from human exfoliated deciduous teeth (SHED-CM) in a mouse RIX model. Intravenous administration of SHED-CM, but not fibroblast-CM (Fibro-CM), prevented radiation-induced cutaneous ulcer formation (p < 0.0001) and maintained SG function (p < 0.0001). SHED-CM treatment enhanced the expression of multiple antioxidant genes in mouse RIX and human acinar cells and strongly suppressed radiation-induced oxidative stress. The therapeutic effects of SHED-CM were abolished by the superoxide dismutase inhibitor diethyldithiocarbamate (p < 0.0001). Notably, quantitative liquid chromatography-tandem mass spectrometry shotgun proteomics of SHED-CM and Fibro-CM identified eight proteins activating the endogenous antioxidant system, which were more abundant in SHED-CM than in Fibro-CM (p < 0.0001). Neutralizing antibodies against those activators reduced antioxidant activity of SHED-CM (anti-PDGF-D; p = 0.0001, anti-HGF; p = 0.003). Our results suggest that SHED-CM may provide substantial therapeutic benefits for RIX primarily through the activation of multiple antioxidant enzyme genes in the target tissue.

Tolerance to intraoral biofilms and their effectiveness in improving mouth dryness and modifying oral microbiota in patients with primary Sjögren's syndrome: "Predelfi study"

INTRODUCTION

Primary Sjögren's syndrome (pSS) is a systemic autoimmune disease characterized by exocrine gland dysfunction. No therapeutic strategy is sufficient on its own for the management of dry mouth and therapeutic innovations are required.

METHODS

This Predelfi study was a single-center, prospective, comparative, randomized, double-blind, cross-over controlled study with the primary objective of assessing the tolerance to and effectiveness of two adhesive biofilms (containing prebiotics and, sodium alginate, respectively) in patients with pSS and hyposialia (#NCT04206826 in ClinicalTrials.gov). Secondary objectives were to obtain initial data regarding the clinical effectiveness of such biofilms in the improvement of signs and symptoms related to dry mouth and potential changes in the oral microbiota. Ten pSS patients with pSS were included (9 females and 1 male) with a mean age of 58.1 ± 14.0 years.

RESULTS AND DISCUSSION

Tolerance to the prebiotic and sodium alginate biofilms was assessed by the patients (visual analog scale [VAS] score 66.7 and 87.6, respectively) and the practitioner (90 and 100, respectively). The absolute changes in the VAS scores at the start and end of each treatment period highlighted an improvement in mouth dryness for the sodium alginate versus the prebiotic biofilm. The VAS scores for other parameters (mouth burning sensation; taste alteration; chewing; swallowing and speech difficulties) remained globally comparable between the two groups. Unstimulated salivary flow showed no changes regardless of the biofilm used. Regarding the oral microbiota, the sodium alginate biofilm increased the abundance of the Treponema genus, whereas the use of the prebiotic biofilm as the first treatment increased the abundance of the genera Veillonella and Prevotella. Nevertheless, the prebiotic biofilm appeared to stimulate "milder" genera with regard to periodontal infections. Furthermore, pre-treatment with the prebiotic biofilm prevented the emergence of the Treponema genus induced by subsequent treatment with the sodium alginate biofilm, suggesting a potential protective effect.

TGFβ1+CCR5+ neutrophil subset increases in bone marrow and causes age-related osteoporosis in male mice

TGFβ1 induces age-related bone loss by promoting degradation of TNF receptor-associated factor 3 (TRAF3), levels of which decrease in murine and human bone during aging. We report that a subset of neutrophils (TGFβ1+CCR5+) is the major source of TGFβ1 in murine bone. Their numbers are increased in bone marrow (BM) of aged wild-type mice and adult mice with TRAF3 conditionally deleted in mesenchymal progenitor cells (MPCs), associated with increased expression in BM of the chemokine, CCL5, suggesting that TRAF3 in MPCs limits TGFβ1+CCR5+ neutrophil numbers in BM of young mice. During aging, TGFβ1-induced TRAF3 degradation in MPCs promotes NF-κB-mediated expression of CCL5 by MPCs, associated with higher TGFβ1+CCR5+ neutrophil numbers in BM where they induce bone loss. TGFβ1+CCR5+ neutrophils decreased bone mass in male mice. The FDA-approved CCR5 antagonist, maraviroc, reduced TGFβ1+CCR5+ neutrophil numbers in BM and increased bone mass in aged mice. 15-mon-old mice with TGFβRII specifically deleted in MPCs had lower numbers of TGFβ1+CCR5+ neutrophils in BM and higher bone volume than wild-type littermates. We propose that pharmacologic reduction of TGFβ1+CCR5+ neutrophil numbers in BM could treat or prevent age-related osteoporosis.

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).

Dental management before radiotherapy of the head and neck region: 4-year single-center experience

OBJECTIVE

To review our experience with a standardized dental management approach in patients with planned radiotherapy of the head and neck region based on preradiation and follow-up data.

MATERIAL AND METHODS

Records of patients who underwent radiotherapy between June 2016 and November 2020 were reviewed. Data on dental findings and therapeutic recommendations were extracted from a prospectively managed database. Hospital records were used to obtain follow-up data.

RESULTS

Two hundred eighty-one patient records were identified. After the exclusion of 81 patients because of incomplete data, 200 patients were included in the study. Dental findings relevant to radiotherapy were found in 144 cases (72.0%). Teeth extractions were recommended in 112 (56.0%) patients. Follow-up data were available for 172 (86.0%) patients (mean follow-up: 16.8 ± 10.7 months). Radiodermatitis was the most frequently observed sequela of radiotherapy (42.4%), followed by dysphagia (38.4%) and stomatitis (36.6%). Osteoradionecrosis was observed in only 2.3% of the patients.

CONCLUSION

Dental findings relevant to planned radiotherapy were frequent and in many cases resulted in recommendations for teeth extraction. Based on our standardized dental management protocol, we observed low rates of late oral complications after radiotherapy of the head and neck region.

Oral functional impairment may cause malnutrition following oral cancer treatment in a single-center cross-sectional study

Oral dysfunction and dysphagia after oral cancer treatment are linked to altered nutritional status. We aimed to identify specific oral functions related to nutritional status. We conducted a cross-sectional study from September 2019 to December 2021, recruited 75 participants (median age: 72.0 years), including 52 males and 23 females, collected background data, and evaluated oral function. The Mini Nutritional Assessment-Short Form (MNA-SF) scores were divided into three groups (normal nutritional status, at risk of malnutrition, and malnourished), and a multi-group comparison was conducted for each oral function measurement (microorganisms, oral dryness, occlusal force, tongue pressure, masticatory function, and Eating Assessment Tool [EAT-10]). The primary tumor site was the tongue in 31 patients (41.3%), gingiva in 30 (40.0%), and others in 14 (18.7%). Multiple comparisons revealed significant differences in occlusal force, tongue pressure, masticatory function, and EAT-10 levels, categorized as Type I (Transport type) and Type III (Occlusion type) postoperative oral dysfunctions, between each MNA-SF group. Multiple regression analysis showed a statistically significant association with MNA-SF in terms of masticatory function and EAT-10 levels, categorized as Type I. Type I and Type III are risk factors for malnutrition, confirming that different types of postoperative oral dysfunction require unique nutritional guidance.

Push-out bond strength of fiber posts to irradiated and non-irradiated intraradicular dentin

OBJECTIVES

The aim of this study is to evaluate the influence of ionizing radiotherapy on the resin-dentin interface in endodontically treated teeth restored with fiber posts using a dual-cure resin cement performed with the etch-and-rinse (ER) and self-etch (SE) approaches in terms of push-out bond strength (MPa), and to analyze the post/cement/dentin interface using scanning electron microscopy (SEM).

MATERIALS AND METHODS

Seventy-six single-rooted human teeth were used and randomly assigned into two main groups (n = 38): one non-irradiated group (NoRad) and one group subjected to a cumulative radiation dose of 60 Gy (Rad). All root canals were instrumented and were further subdivided into two subgroups (n = 19) following the adhesive approach: ER (RadER; NoRadER) and SE (RadSE; NoRadSE) used for fiber post luting with the universal adhesive and dual cure resin cement. Each root was sectioned perpendicularly to its long axis and sections from the middle third of the roots were chosen for SEM analysis and push-out bond strength test. Two-way ANOVA with post hoc Tukey tests and a dummy variable linear regression analysis were used for data analysis.

RESULTS

Regardless of the adhesive approach, push-out bond strength in irradiated teeth resulted in significantly lower values than non-irradiated teeth (p = 0.0001). There were no significant differences between the ER and SE approaches in non-irradiated teeth (p = 0.955), whereas the ER approach showed significantly higher bond strengths than the SE approach in irradiated teeth (p = 0.0001).

CONCLUSIONS

Ionizing radiotherapy resulted in dentin structure disruption and negatively affected the push-out bond strength of fiber posts to intraradicular dentin. The reduction in bond strength was also more significant with the SE approach than with the ER approach.

CLINICAL RELEVANCE

The alterations resulting from root dentin irradiation seem to influence adhesive systems bond strength to dentin, as these changes contribute to lower push-out bond strength in irradiated groups before fiber post luting. Thus, clinicians should prepare patients with a reasonable restorative treatment plan prior to radiotherapy and simultaneously initiate a preventive program during radiotherapy.

Effect of experimental and commercial artificial saliva formulations on the activity and viability of microcosm biofilm and on enamel demineralization for irradiated patients with head and neck cancer (HNC)

The effect of different artificial saliva formulations on biofilm activity and viability, and on enamel demineralization for head and neck cancer (HNC) patients was evaluated. Irradiated enamel samples were treated (1 min) with BioXtra® or with experimental formulations containing carboxymethylcellulose plus inorganic constituents alone (AS) or containing 0.1 mg mL^-1 CaneCPI-5 (AS + Cane), 1.0 mg mL^-1 hemoglobin (AS + Hb) or combination of both (AS + Cane + Hb). Phosphate-buffered-saline and chlorhexidine (0.12%) were negative and positive control, respectively. Biofilm was produced from the saliva of five male HNC patients, under 0.2% sucrose exposure for 5 days, and daily treated with the formulations (1 min). No significant effects were observed for the different experimental treatments. BioXtra^® significantly reduced lactobacilli, demonstrating antibacterial potential for this group. Chlorhexidine was an effective treatment to significantly reduce all parameters, being an important antimicrobial and anticaries agent. Future in vitro studies must be performed using a new approach for the design of the experimental formulations.

Over 300 Radiation Caries Papers: Reflections From the Rearview Mirror

Radiation caries (RC) is an aggressive oral toxicity in head and neck cancer survivors, which develops 6 to 12 months after head and neck radiotherapy. It initially affects the tooth cervical/incisal surfaces, and if not promptly diagnosed/managed, progresses to dental crown amputation and risk of osteoradionecrosis. It results from a multidimensional cluster of treatment-induced oral symptoms, including hyposalivation, dietary changes, and oral hygiene impairment. Although recognized as a frequent complication of radiotherapy and extensively assessed by a myriad of retrospective, in vitro, and in situ studies, RC patients are still orphans of clinically validated methods for risk prediction, prevention, and treatment of early lesions. This review provides a historical overview of science-based concepts regarding RC pathogenesis and treatment, emphasizing the growing demand for interventional clinical studies (randomized trials).

Tooth Formation as Experimental Model to Study Chemotherapy on Tissue Development: Effect of a Specific Dose of Temozolomide/Veliparib

Background: Chemotherapy treatment of cancer in children can influence formation of normal tissues, leading to irreversible changes in their structure and function. Tooth formation is susceptible to several types of chemotherapy that induce irreversible changes in the structure of enamel, dentin and dental root morphology. These changes can make the teeth more prone to fracture or to caries when they have erupted. Recent studies report successful treatment of brain tumors with the alkylating drug temozolomide (TMZ) in combination with veliparib (VLP) in a glioblastoma in vivo mouse model. Whether these drugs also affect tooth formation is unknown. Aim: In this study the effect of TMZ/VLP on incisor formation was investigated in tissue sections of jaws from mice and compared with mice not treated with these drugs. Materials and method: The following aspects were studied using immunohistochemistry of specific protein markers including: (1) proliferation (by protein expression of proliferation marker Ki67) (2) a protein involved in paracellular ion transport (expression of tight junction (TJ) protein claudin-1) and (3) in transcellular passage of ions across the dental epithelium (expression of Na+, K+ 2Cl- cotransporter/NKCC1). Results: Chemotherapy with TMZ/VLP strongly reduced immunostaining for claudin-1 in distal parts of maturation ameloblasts. No gross changes were found in the treated mice, either in cell proliferation in the dental epithelium at the cervical loop or in the immunostaining pattern for NKCC1 in (non-ameloblastic) dental epithelium. The salivary glands in the treated mice contained strongly reduced immunostaining for NKCC1 in the basolateral membranes of acinar cells. Discussion/Conclusions: Based on the reduction of claudin-1 immunostaining in ameloblasts, TMZ/VLP may potentially influence forming enamel by changes in the structure of TJs structures in maturation ameloblasts, structures that are crucial for the selective passage of ions through the intercellular space between neighboring ameloblasts. The strongly reduced basolateral NKCC1 staining seen in fully-grown salivary glands of TMZ/VLP-treated mice suggests that TMZ/VLF could also influence ion transport in adult saliva by the salivary gland epithelium. This may cause treated children to be more susceptible to caries.

Considerations for restorative dentistry secondary care referrals - part 1: defining strategic importance

Strategic importance is an essential concept for dental service providers. It allows clinicians to differentiate treatment needs on both a patient level and a health care commissioning level, not simply based upon complexity alone. On a patient level, it influences both the clinician's and patient's decision as to whether a tooth/teeth should be restored, as well as determining the possible need for specialist input. On a commissioning level, it facilitates the prioritisation of limited resources.

Strategic importance can be considered at a patient level, taking into factors such as age, tolerance to treatment and the patient's choice. It can also be considered at a mouth level, accounting for factors such as its impact on function and aesthetics function. All these factors together can influence the decision as to whether complex treatment is warranted on a given tooth, especially in a healthcare model where the allocation of limited resources is necessary.

An assessment of strategic importance should be carried out before treatment planning or onward referral to a secondary/tertiary care unit.

Outlines the key considerations for determining strategic importance at a systemic and local level.

Takes into account strategic importance before treatment may be essential in allowing the allocation of resources in both primary and secondary care.

Color stability and microhardness alteration of irradiated dental enamel treated with a high fluoride concentration toothpaste

OBJECTIVES

Radiotherapy (RT) is a kind of head and neck cancer (HNC) treatment, which is associated to the habit of smoking and can develop collateral effects in the oral cavity, such as the increase of caries prevalence. This study evaluated the color alteration, the microhardness, and the remineralizing potential of high fluoride concentration toothpastes on irradiated teeth.

MATERIALS AND METHODS

Forty bovine teeth were used (6 × 6 × 2 mm) and after color (EasyShade, VITA) and microhardness initial readings were separated into two groups: exposed to cigarette smoke and non-exposed. All samples were submitted to RT (30 Gy) and to cariogenic challenge. New color and microhardness readings were done. After RT (60 Gy), the samples were submitted to simulated toothbrushing (73,000 cycles = 5 years of brushing) with two different toothpastes: conventional (1450 ppm) and high fluoride concentration (5000 ppm). Final color and microhardness readings were done after brushing. Data were analyzed with 2-way ANOVA with repeated measures and Tukey's test (p < .05).

RESULTS

There was no color difference after RT, nor after brushing (p > .05). However, after brushing, microhardness values increased for the samples treated with high fluoride concentration toothpaste (p < .05).

CONCLUSION

Radiotherapy did not influence the teeth color, and the high fluoride concentration toothpaste presented remineralizing potential; therefore, it could be used on the caries prevention related to HNC radiation.

CLINICAL RELEVANCE

Considering its remineralizing potential, toothpastes with high fluoride concentration could be a proper alternative for caries prevention in patients undergoing radiotherapy.

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.

Effects of irradiation, restoration and crown fracture type on the maximum load to fracture traumatized incisors: An ex vivo study

BACKGROUND/AIMS

Radiotherapy makes teeth prone to tooth fractures. However, the relationship between radiotherapy and maximum load to fracture teeth that suffered a crown fracture is not fully understood. The aim of this study was to evaluate the influence of fracture type, radiation dose, fracture time, and their interactions on maximum load to fracture irradiated teeth.

MATERIAL AND METHODS

A total of 140 permanent incisors were divided into two fracture type groups (uncomplicated and complicated) each of which included seven radiation dose subgroups (0, 10, 20, 30, 40, 50, and 60). The test groups were exposed to high-energy X-ray at 2 Gy/day, 5 days/week for a total dose of 10-60 Gy. Control groups were not irradiated. The load where the specimen started to break was obtained two different times. The 1st fracture was performed after radiation therapy, and the 2nd fracture was performed after the restoration of these samples.

RESULTS

Fracture type had no effect on the maximum load to fracture. In contrast, the maximum load to fracture teeth decreased with increasing radiation doses. Maximum load to fracture the restored teeth was lower than the 1st fracture results. The general linear model procedure revealed a significant interaction between radiation dose and fracture time. Similarly, there was a significant interaction between the fracture type, radiotherapy dose, and fracture time. Maximum load values of teeth with complicated crown fractures restored with fiber posts and composite were not affected by radiation.

CONCLUSION

Teeth that have been subjected to radiotherapy have an increased risk of fracture during dental trauma. However, restoration of the irradiated teeth with fiber posts and composite resin did not affect the maximum load required to fracture them.

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.

Head and neck radiotherapy effects on the dental pulp vitality and response to sensitivity tests. A systematic review with meta-analysis

BACKGROUND

There is no consensus whether radiotherapy for head and neck cancer (HNC) could induce pulp necrosis. Therefore, a systematic review of clinical studies is necessary.

OBJECTIVES

To evaluate the evidences on radiotherapy for HNC and pulp status.

METHODS

A systematic search of articles published until November 2021 was performed in the MEDLINE/PubMed, Cochrane Library, Web of Science (All Databases), Scopus, EMBASE and Open Grey databases. The eligibility criteria were based on the PICOS strategy, as follows: (P) vital teeth of adult patients with intraoral and/or oropharyngeal cancer; (I) radiotherapy; (C) control group or values of the same tooth before radiotherapy (basal values); (O) pulpal status after radiotherapy; (S) clinical studies. The Cochrane Risk Of Bias In Non-randomised Studies - of Interventions (ROBINS-I) tool was used to assess the quality of the included studies. Meta-analyses were performed using fixed and random effects. The overall quality of evidence was assessed through the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) tool.

RESULTS

Six studies were included for qualitative analysis. Five were classified as serious risk of bias and one as moderate risk of bias. Four studies reported altered pulp responses to cold thermal test after radiotherapy initiation. Meta-analyses were performed using three included studies. From these, all were included in the meta-analysis for pulp response values to cold sensitivity test immediately after radiotherapy initiation (risk ratio: 0.00[CI:0.00, 0.02], P < 0.00001; I² = 0%); and two in the meta-analysis for pulp response values to cold sensitivity test after 4-5 months of radiotherapy (risk ratio: 0.01[CI: 0.00. 0.06], P < 0.00001; I² = 0%). Two reported progressively higher readings to pulp response in the electrical test after radiotherapy initiation (mean difference: -11.46[-13.09, -9.84], P < 0.00001; I² = 68%) and at all periods evaluated. Two studies demonstrated a pulp oxygen saturation (SpO₂ ) decrease at the end of radiotherapy; and increase after 4-6 months of radiotherapy beginning. And other demonstrated normal dental pulp SpO₂ 4 to 6 years after treatment. GRADE analysis presented a moderate certainty of evidence.

DISCUSSION

This review verified that radiotherapy for HNC causes significant alterations on the dental pulp responses, but does not seem to induce pulp necrosis. Significant limitations regarding controlling for confounding factors, classification of interventions and measurement of outcomes were verified, evidencing the need for well-designed studies.

CONCLUSIONS

This systematic review demonstrated that radiotherapy for HNC induced significant changes in the pulp response with moderate quality of evidence. Such altered responses cannot determine pulp status accurately.

The prevalence of dental developmental anomalies among childhood cancer survivors according to types of anticancer treatment

Survival following childhood cancer has increased considerably. In an observational cross-sectional study, we assessed the prevalence of dental developmental anomalies (DDA) among childhood cancer survivors according to types of anticancer treatment. Permanent teeth were examined clinically and radiographically in 121 adolescents with a history of childhood malignancies, to identify DDA, namely hypomineralization or hypoplasia, microdontia, root changes and hypodontia. DDA were observed in 56/121 individuals (46%), in 309/3388 teeth (9%). Hypomineralization or hypoplasia of enamel appeared in 21 (17%) patients. Altered root development appeared in 26 patients and hypodontia affected 13 (10%). Dental anomalies were observed in 36 (43%) individuals who received chemotherapy and not radiation, in 20 (52%) who received radiotherapy, and in 15 (60%) of those who received head and neck radiotherapy. Among patients who received only chemotherapy, young age (6 years or younger) was associated with a higher number of malformed teeth. In conclusion, antineoplastic treatment that combines chemotherapy and radiotherapy appears to increase the risk of DDA. Radiation to the head and neck area was shown to particularly increase the risk of DDA. No specific chemotherapy agent was found to be associated more than the others with DDA.

Oral Health Status in Patients with Head and Neck Cancer before Radiotherapy: Baseline Description of an Observational Prospective Study

(1) Background: The general hypothesis that HNC patients show compromised oral health (OH) is generally accepted, but it is not evidence-based. The objective of this baseline report of a prospective observational study was to describe the oral health of a cohort of patients with HNC at the time of dental evaluation prior to radiotherapy (RT). (2) Materials and Methods: Two hundred and thirteen patients affected by HNC who had received an indication for RT were examined with the support of orthopantomography (OPT). The DMFt of all included subjects, their periodontal status and the grade of mouth opening were recorded. (3) Results: A total of 195 patients were ultimately included: 146/195 patients (74.9%) showed poor OH (defined as having a DMFt score ≥ 13 and severe periodontitis). The following clinical characteristics were correlated with poor oral health in the univariate analysis: tumor site, smoking habit and age of the patients (in decades); χ2 test, p < 0.05. (4) Conclusions: This study confirms that the OH of HNC patients is often compromised even before the beginning of cancer treatment and, consequently, highlights how important it is to promptly schedule a dental evaluation at the moment of diagnosis of the cancer.

Dental extraction, intensity-modulated radiotherapy of head and neck cancer, and osteoradionecrosis : A systematic review and meta-analysis

Objective

To seek evidence for osteoradionecrosis (ORN) after dental extractions before or after intensity-modulated radiotherapy (IMRT) for head and neck cancer (HNC).

Methods

Medline/PubMed, Embase, and Cochrane Library were searched from 2000 until 2020. Articles on HNC patients treated with IMRT and dental extractions were analyzed by two independent reviewers. The risk ratios (RR) and odds ratios (OR) for ORN related to extractions were calculated using Fisher’s exact test. A one-sample proportion test was used to assess the proportion of pre- versus post-IMRT extractions. Forest plots were used for the pooled RR and OR using a random-effects model.

Results

Seven of 630 publications with 875 patients were eligible. A total of 437 (49.9%) patients were treated with extractions before and 92 (10.5%) after IMRT. 28 (3.2%) suffered from ORN after IMRT. ORN was associated with extractions in 15 (53.6%) patients, eight related to extractions prior to and seven cases related to extractions after IMRT. The risk and odds for ORN favored pre-IMRT extractions (RR = 0.18, 95% CI: 0.04–0.74, p = 0.031, I² = 0%, OR = 0.16, 95% CI: 0.03–0.99, p = 0.049, I² = 0%). However, the prediction interval of the expected range of 95% of true effects included 1 for RR and OR.

Conclusion

Tooth extraction before IMRT is more common than after IMRT, but dental extractions before compared to extractions after IMRT have not been proven to reduce the incidence of ORN. Extractions of teeth before IMRT have to be balanced with any potential delay in initiating cancer therapy.

Supplementary Information

The online version of this article (10.1007/s00066-021-01896-w) contains supplementary material, which is available to authorized users.

Direct Induced Effects of Standard and Modified Radiotherapy Protocol on Surface Structure of Hard Dental Tissue

Introduction

Radiotherapy is used to treat neo plasmatic lesions and the common side effects of this process are pain, swelling and sensitivity of mucous membranes in domain of radiation, reduced salivation, caries, and periodontal disease and, in total, low life quality. The purpose of this research was to estimate the outcome of direct irradiation on physical and surface characteristics of hard dental tissues.

Materials and methods

Twenty, caries free third molars were involved in the research. Prior to different submission protocols, tooth halves were randomly assigned to subject and control groups by using a draw method. The first group (n=20) was submitted to conventional irradiation protocol (2 Gy for 35 days), second group (n=20) was submitted to one powerful, exploratory dose of 70 Gy. Each sample served as its own control. Radiation was performed with a linear accelerator radiotherapy unit. The surface microhardness and roughness were measured at the beginning (initially), and upon completion of irradiation procedure. The average change in microhardness and roughness after different treatments was compared by t-test for independent samples. Normality was tested by the Shapiro-Wilk test.

Results

Significant differences were found after the standard radiation protocol and the exploratory dose of 70 Gy, with decreased mean microhardness and increased mean roughness (p<0.001) of both hard dental tissues. Enamel and dentin surface microhardness and roughness did not vary notably with regards to different irradiation protocols.

Conclusion

Head and neck conventional irradiation protocol leads to possible breakdown of enamel and dentin with reduced microhardness and increased surface roughness regardless of used irradiation protocol.

Review of Cracked Tooth Syndrome: Etiology, Diagnosis, Management, and Prevention

Cracked tooth syndrome refers to a series of symptoms caused by cracked teeth. This article reviews the current literature on cracked tooth syndrome from four aspects, etiology, diagnosis, management, and prevention, to provide readers integrated information about this. The article begins with an introduction to the odontiatrogenic factors and then covers the noniatrogenic factors that induce cracked tooth syndrome. While the former discusses inappropriate root canal therapy and improper restorative procedures, the latter covers the topics such as the developmental and functional status of cracked tooth syndrome. This is then followed by the description of common clinical diagnosis methods, the prospects of new technologies, and summaries of current clinical management methods, including immediate management and direct and indirect restoration. In the final section, preventive methods and their importance are proposed, with the aim of educating the common population.

Osteoradionecrosis of the Jaws Due to Teeth Extractions during and after Radiotherapy: A Systematic Review

Teeth extractions before or after radiotherapy (RT) could be procedures at high risk for osteoradionecrosis (ORN) onset. This systematic review was performed to investigate the ORN incidence following teeth extractions during and after RT for head and neck (H&N) cancer and to evaluate any other possible risk factor.

METHODS

This systematic review was conducted according to PRISMA protocol, and the PROSPERO registration number was CRD42018079986. An electronic search was performed on the following search engines: PubMed, Scopus, and Web of Science. A cumulative meta-analysis was performed.

RESULTS

Two thousand two hundred and eighty-one records were screened, and nine were finally included. This systematic review revealed an ORN incidence of 5.8% (41 patients out of 462, 95% CI = 2.3-9.4); 3 ORN developed in the maxilla. No other clinical risk factors were detected.

CONCLUSION

Post-RT teeth extractions represent a major risk factor for ORN development, especially in the mandible, with a diminishing trend in the last years. Further research on other possible risk factors might improve this evidence.

Dental loss after radiotherapy for head and neck cancer

Introduction In radiotherapy (RT) for head and neck cancer (HNC), dental morbidity is significant and it may result in loss of the dentition following treatment.Aims The aim of this clinical study is to identify the incidence of tooth loss over time and correlate this to the RT dose and various risk factors in patients with HNC treated with radical RT.Design A retrospective observational study.Materials and methods The records of 1,118 patients with HNC treated with radical or adjuvant RT from January 2010 to December 2019 were analysed. After applying strict inclusion criteria, 78 patients with 1,566 individual tooth data were selected. RT dose mapping was performed for each tooth.Results A total of 253 teeth (16.2%) were extracted. The following risk factors were significant: gender (p = 0.0001), xerostomia (p <0.0001), RT dose (p <0.0001) and smoking (p <0.0001). Non-significant factors were age, RT delivery technique and the addition of cisplatin.Conclusion Detailed RT dose mapping was used to identify RT dose as a risk factor for dental loss. Careful pre-RT dental treatment and minimisation of RT dose to teeth and salivary glands is required to prevent or reduce the loss of dentition.

Direct Radiotherapy-Induced Effects on Dental Hard Tissue in Combination With Bleaching Procedure

Introduction: The aim of this study was to evaluate the effects of radiation and tooth bleaching on the physical and morphological properties of enamel and dentin on permanent teeth.

Materials and Methods: Eighty fresh, non-carious third molars were used in this study. Before cutting the crown in half, the teeth samples were randomly allocated to treatment and control groups by using a lottery method. The first group (n = 20) underwent standard radiation protocol (2 Gy/fraction/day, 5 days/week) with bleaching treatment afterward using 16% carbamide peroxide gel, the second group (n = 20) underwent standard radiation protocol with afterward bleaching treatment using 38% hydrogen peroxide, the third group (n = 20) underwent a short, one strong, experimental dose of 70 Gy with afterward bleaching treatment using 16% carbamide peroxide gel, and the fourth group (n = 20) underwent one strong, experimental dose of 70 Gy with afterward bleaching treatment using 38% hydrogen peroxide gel. Groups 5–8 (n = 20) served as control as they underwent only bleaching treatment. Vickers microhardness and surface roughness were performed before (initial) and after irradiation and before bleaching or after only bleaching. The effects of irradiation and bleaching on microhardness (or roughness) of enamel and dentin were analyzed in the repeated-measures ANOVA model.

Results: Enamel microhardness after experimental single 70-Gy irradiation or after standard radiation protocol and bleaching with 16 or 38% gel was not statistically significant from microhardness in the control group (p &gt; 0.05). There was a statistically significantly greater reduction in the average microhardness of enamel and dentin during bleaching with 38% gel compared to 16% for both radiation protocols (p &lt; 0.001). After experimental 70-Gy irradiation and bleaching, a 16% statistically significant increase in surface roughness was found for enamel (p = 0.006) and dentin (p = 0.018), while this was not recorded for 38% gel. There was a statistically significantly greater increase in the average roughness of enamel and dentin during bleaching with 38% gel compared to 16% (p &lt; 0.001) for both radiation protocols.

Conclusions: Directly induced radiation leads to potential damage of hard dental tissues, which can be further damaged by additional bleaching. If teeth whitening is necessary after irradiation, it is suggested to use lower concentrations of whitening gels.

Impact of radiation on tooth loss in patients with head and neck cancer: a retrospective dosimetric-based study

OBJECTIVE

To characterize the dental adverse events after head and neck radiation therapy (HNRT) and to investigate the impact of regional radiation dose upon tooth loss outcomes.

STUDY DESIGN

A retrospective dosimetric-based analysis was conducted to assess dental events affecting post-HNRT extracted teeth and the impact of 3 different radiation doses (<30 Gy, 30-60 Gy, and >60 Gy) upon tooth loss. In addition, post-HNRT extractions outcomes and mean parotid glands dosimetry and salivary changes were analyzed.

RESULTS

Sixty-six patients who underwent HNRT were included in the analysis. Radiation caries was the most frequent (67.8%) post-HNRT dental adverse event, and maxillary molars ipsilateral to the tumor were lost earlier compared with the others (P < .001). The odds ratio for post-HNRT tooth extraction risk was approximately 3-fold higher for teeth exposed to >60 Gy (confidence interval, 1.56-5.35; P < .001), followed by an increased risk of delayed healing and osteoradionecrosis (ORN) in sites receiving doses above 50 Gy.

CONCLUSIONS

Radiation caries was the major cause of dental extractions after HNRT, and the dosimetric analysis suggested that a high dose of radiation may negatively impact the dentition of survivors of head and neck cancer, increasing the risk of tooth loss and ORN.

Dosimetric Parameters Predicting Tooth Loss after Carbon Ion Radiotherapy for Head and Neck Tumors

Background: Tooth loss reduces quality of life; however, little is known about tooth loss caused by carbon ion radiotherapy (CIRT). Here, we aimed to elucidate the incidence of tooth loss post-CIRT for head and neck tumors and to identify risk-predictive dosimetric parameters. Methods: This study enrolled 14 patients (i.e., 171 teeth in total) with head and neck non-squamous cell carcinoma. All patients received CIRT comprised of 57.6 or 64.0 Gy (relative biological effectiveness, RBE) in 16 fractions. Dose–volume analysis of the teeth was performed using receiver operating characteristic (ROC) curve analysis with VX (i.e., the volume irradiated with X Gy (RBE)). Results: The median follow-up period was 69.1 months. The median time of tooth loss was 38.6 months. The 5 year cumulative incidence of tooth loss was 13.3%. The volume of irradiated teeth was significantly greater for the lost teeth than for the remaining teeth throughout the dose range. Using the cut-offs calculated from ROC curve analysis, V30–V60 showed high accuracy (i.e., >94%) for predicting tooth loss, with V50 being the most accurate (cut-off, 58.1%; accuracy, 0.95). Conclusions: This is the first report to examine the incidence of tooth loss post-CIRT and to identify risk-predictive dosimetric parameters.

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.

Effects of ionizing radiation on surface properties of current restorative dental materials

To investigate the impact of radiotherapy on surface properties of restorative dental materials. A conventional resin composite-CRC (Aura Enamel), a bulk-fill resin composite-BFRC (Aura Bulk-fill), a conventional glass ionomer cement-CGIC (Riva self cure), and a resin-modified glass ionomer cement-RMGIC (Riva light cure) were tested. Forty disc-shaped samples from each material (8 mm diameter × 2 mm thickness) (n = 10) were produced according to manufacturer directions and then stored in water distilled for 24 h. Surface wettability (water contact angle), Vickers microhardness, and micromorphology through scanning electron microscopy (SEM) before and after exposition to ionizing radiation (60 Gy) were obtained. The data were statistically evaluated using the two-way ANOVA and Tukey posthoc test (p < 0.05). Baseline and post-radiation values of contact angles were statistically similar for CRC, BFRC, and RMGIC, whilst post-radiation values of contact angles were statistically lower than baseline ones for CGIC. Exposition to ionizing radiation statistically increased the microhardness of CRC, and statistically decreased the microhardness of CGIC. The surface micromorphology of all materials was changed post-radiation. Exposure to ionizing radiation negatively affected the conventional glass ionomer tested, while did not alter or improved surface properties testing of the resin composites and the resin-modified glass ionomer cement tested.

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.