Oral complications of radiotherapy in the head and neck

Advances in hybridized nanoarchitectures for improved oro-dental health

On a global note, oral health plays a critical role in improving the overall human health. In this vein, dental-related issues with dentin exposure often facilitate the risk of developing various oral-related diseases in gums and teeth. Several oral-based ailments include gums-associated (gingivitis or periodontitis), tooth-based (dental caries, root infection, enamel erosion, and edentulous or total tooth loss), as well as miscellaneous diseases in the buccal or oral cavity (bad breath, mouth sores, and oral cancer). Although established conventional treatment modalities have been available to improve oral health, these therapeutic options suffer from several limitations, such as fail to eradicate bacterial biofilms, deprived regeneration of dental pulp cells, and poor remineralization of teeth, resulting in dental emergencies. To this end, the advent of nanotechnology has resulted in the development of various innovative nanoarchitectured composites from diverse sources. This review presents a comprehensive overview of different nanoarchitectured composites for improving overall oral health. Initially, we emphasize various oral-related diseases, providing detailed pathological circumstances and their effects on human health along with deficiencies of the conventional therapeutic modalities. Further, the importance of various nanostructured components is emphasized, highlighting their predominant actions in solving crucial dental issues, such as anti-bacterial, remineralization, and tissue regeneration abilities. In addition to an emphasis on the synthesis of different nanostructures, various nano-therapeutic solutions from diverse sources are discussed, including natural (plant, animal, and marine)-based components and other synthetic (organic- and inorganic-) architectures, as well as their composites for improving oral health. Finally, we summarize the article with an interesting outlook on overcoming the challenges of translating these innovative platforms to clinics.

Assessing push-out bond strength in re-irradiated teeth: Universal resin cement performance in self-etch and self-adhesive modes

OBJECTIVES

To investigate the effect of cumulative doses of radiation on the pushout bond strength (BS) of a universal resin cement used in the self-etch (SE) and self-adhesive (SA) modes to the intraradicular dentin.

MATERIALS AND METHODS

Forty-eight human teeth were distributed into three groups (n = 16) according to the radiation therapy dose (RT): NoRT (no-radiotherapy), 70RT (70 Gy), and 70 + 70RT (70 Gy + 70 Gy). The teeth were redistributed into two subgroups (n = 8), according to the adhesive mode: SE (NoRT-SE, 70RT-SE, and 70 + 70RT-SE) and SA (NoRT-SA, 70RT-SA, and 70 + 70RT-SA). Data were statistically compared after BS test (ANOVA, Tukey's post hoc test, and Fisher's exact test).

RESULTS

In the SA mode, BS was significantly higher in nonirradiated teeth compared with 70RT and 70 + 70RT (p < 0.0001). There were no significant differences between SE and SA modes in nonirradiated teeth (p = 0.14). In the 70RT group, SE mode increased BS compared with SA mode (p < 0.0001). Most specimens had adhesive and mixed failures in SA and SE modes, respectively.

CONCLUSIONS

The universal resin cement in the SE mode had greater BS to the irradiated dentin. When teeth were re-irradiated, the universal resin cement had similar performance in terms of BS, regardless of the adhesive approach.

CLINICAL SIGNIFICANCE

There is no research establishing a correlation between radiotherapy and its impact on the BS of a universal resin cement used in SE and SA modes to intraradicular dentin.

Assessment of multispecies biofilm growth on root canal dentin under different radiation therapy regimens

OBJECTIVES

To assess the growth of a multispecies biofilm on root canal dentin under different radiotherapy regimens.

MATERIALS AND METHODS

Sixty-three human root dentin cylinders were distributed into six groups. In three groups, no biofilm was formed (n = 3): NoRT) non-irradiated dentin; RT55) 55 Gy; and RT70) 70 Gy. In the other three groups (n = 18), a 21-day multispecies biofilm (Enterococcus faecalis, Streptococcus mutans, and Candida albicans) was formed in the canal: NoRT + Bio) non-irradiated + biofilm; RT55 + Bio) 55 Gy + biofilm; and RT70 + Bio) 70 Gy + biofilm. The biofilm was quantified (CFUs/mL). Biofilm microstructure was assessed under SEM. Microbial penetration into dentinal tubules was assessed under CLSM. For the biofilm biomass and dentin microhardness pre- and after biofilm growth assessments, 45 bovine dentin specimens were distributed into three groups (n = 15): NoRT) non-irradiated + biofilm; RT55 + Bio) 55 Gy + biofilm; and RT70 + Bio) 70 Gy + biofilm.

RESULTS

Irradiated specimens (70 Gy) had higher quantity of microorganisms than non-irradiated (p = .010). There was gradual increase in biofilm biomass from non-irradiated to 55 Gy and 70 Gy (p < .001). Irradiated specimens had greater reduction in microhardness after biofilm growth. Irradiated dentin led to the growth of a more complex and irregular biofilm. There was microbial penetration into the dentinal tubules, regardless of the radiation regimen.

CONCLUSION

Radiotherapy increased the number of microorganisms and biofilm biomass and reduced dentin microhardness. Microbial penetration into dentinal tubules was noticeable.

CLINICAL RELEVANCE

Cumulative and potentially irreversible side effects of radiotherapy affect biofilm growth on root dentin. These changes could compromise the success of endodontic treatment in oncological patients undergoing head and neck radiotherapy.

Chemotherapy increases the prevalence of radiotherapy-related trismus in head and neck cancer patients: A systematic review and meta-analysis

Background

To evaluate the influence of chemotherapy on the prevalence of trismus in irradiated head and neck cancer patients.

Material and Methods

This systematic review guided by PRISMA-2020 and registered in PROSPERO (CRD42021255377) screened 963 articles in 7 scientific-databases (PubMed, Lilacs, Livivo, Scopus, Embase, Web of Science, EBSCO) and 3 grey-literature databases (Open Grey, Google Scholar, ProQuest) and eight articles were included for qualitative synthesis, meta-analysis (combined odds ratio, inverse variance method plus random effects), heterogeneity analysis (I² and Tau²), one-of-out evaluation and publication bias analysis (Eggs' and Begg's tests) (RevMan®, p<0.05). The Newcastle-Ottawa Quality Assessment Scale Cohort Studies was used to assess the risk of bias (RoB). The classification assessment, development, and recommendations (GRADE) approach was used to assess the certainty of evidence.

Results

The eight articles evaluated 1474 patients treated with chemoradiotherapy and 858 patients treated with radiotherapy. Five articles had low RoB, and three had high RoB. Chemoradiotherapy significantly (p=0.0003) increased the prevalence of trismus (OR=2.55, 95% CI = 1.53-4.23) compared to radiotherapy, with significant (p=0.010) but low heterogeneity (I²=59%;Tau²=0.29). There was no significant risk of publication bias, one-out analysis showed no significant difference between studies, and GRADE showed a moderate level of evidence. Trismus was directly associated to worse quality of life.

Conclusions

The incidence of trismus increases when chemotherapy is combined with radiotherapy for head and neck cancer, which negatively impacts the quality of life. Key words:Radiotherapy, Chemoradiotherapy, Head and Neck Neoplasms, Trismus, Quality of Life.

In vivo modeling recapitulates radiotherapy delivery and late-effect profile for childhood medulloblastoma

Background

Medulloblastoma (MB) is the most common malignant pediatric brain tumor, with 5-year survival rates > 70%. Cranial radiotherapy (CRT) to the whole brain, with posterior fossa boost (PFB), underpins treatment for non-infants; however, radiotherapeutic insult to the normal brain has deleterious consequences to neurocognitive and physical functioning, and causes accelerated aging/frailty. Approaches to ameliorate radiotherapy-induced late-effects are lacking and a paucity of appropriate model systems hinders their development.

Methods

We have developed a clinically relevant in vivo model system that recapitulates the radiotherapy dose, targeting, and developmental stage of childhood medulloblastoma. Consistent with human regimens, age-equivalent (postnatal days 35-37) male C57Bl/6J mice received computerized tomography image-guided CRT (human-equivalent 37.5 Gy EQD2, n = 12) ± PFB (human-equivalent 48.7 Gy EQD2, n = 12), via the small animal radiation research platform and were longitudinally assessed for > 12 months.

Results

CRT was well tolerated, independent of PFB receipt. Compared to a sham-irradiated group (n = 12), irradiated mice were significantly frailer following irradiation (frailty index; P = .0002) and had reduced physical functioning; time to fall from a rotating rod (rotarod; P = .026) and grip strength (P = .006) were significantly lower. Neurocognitive deficits were consistent with childhood MB survivors; irradiated mice displayed significantly worse working memory (Y-maze; P = .009) and exhibited spatial memory deficits (Barnes maze; P = .029). Receipt of PFB did not induce a more severe late-effect profile.

Conclusions

Our in vivo model mirrored childhood MB radiotherapy and recapitulated features observed in the late-effect profile of MB survivors. Our clinically relevant model will facilitate both the elucidation of novel/target mechanisms underpinning MB late effects and the development of novel interventions for their amelioration.

Fibrin hydrogels fortified with FGF-7/10 and laminin-1 peptides promote regeneration of irradiated salivary glands

Ionizing radiation, commonly used for head and neck cancer treatment, typically damages the salivary glands, resulting in hyposalivation. The development of treatments to restore this lost function is crucial for improving the quality of life for patients suffering from this condition. To address this clinical need, we have developed an innovative hydrogel by chemically conjugating laminin-1 peptides (A99 and YIGSR) and growth factors, FGF-7 and FGF-10, to fibrin hydrogels. Our results demonstrate that FGF-7/10 and laminin-1 peptides fortified fibrin hydrogel [enhanced laminin-1 peptides fibrin hydrogel (Ep-FH)] promotes salivary gland regeneration and functionality by improving epithelial tissue organization, establishing a healthy network of blood vessels and nerves, while reducing fibrosis in a head and neck irradiated mouse model. These results indicate that fibrin hydrogel-based implantable scaffolds containing pro-regenerative signals promote sustained secretory function of irradiated salivary glands, offering a potential alternative treatment for hyposalivation in head and neck cancer patients undergoing radiation treatment. These unique findings emphasize the potential of fibrin hydrogel-based implantable scaffolds enriched with pro-regenerative signals in sustaining the secretory function of irradiated salivary glands and offer a promising alternative treatment for addressing hyposalivation in head and neck cancer patients undergoing radiation therapy. STATEMENT OF SIGNIFICANCE: Radiation therapies used to treat head and neck cancers often result in damaged salivary gland, leading to severe dryness of the oral cavity. In this study, we engineered FGF-7 and FGF-10 and immobilized them into L1p-FH. The resulting hydrogel, Ep-FH, restored irradiated salivary gland functionality by enhancing epithelial tissue organization, promoting the development of a healthy network of blood vessels and nerves as well as reduction of fibrosis.

Photobiomodulation therapy in the treatment of radiotherapy-related trismus of the head and neck

This study evaluated photobiomodulation therapy (PBMT) for treatment of trismus in patients undergoing radiotherapy for head and neck cancer (HNC). Sixteen patients, 10 men and 6 women, who had a mouth opening < 35 mm and underwent RT were included. The patients were evaluated daily before and after the PBMT application, measuring mouth opening and performing pain scores for the masticatory muscles using the visual analog scale (VAS). We used the infrared laser (~ 808 nm) extraorally, 0.1 W power, 3 J energy, 30 s (107 J/cm2) per point, applied to temporalis anterior, masseter muscles, and temporomandibular joints (TMJ). An intraoral point was made in the trigonoretromolar region towards the medial pterygoid muscle. The mean mouth opening of the patients increased by more than 7 mm throughout the treatment. The pain scores on the initial days showed an immediate reduction after PBMT on the ipsilateral side in the muscles and TMJ. Throughout PBMT applications, there was a significant reduction in pain scores in all muscles and the TMJ. The radiation dose of all patients was above 40 Gy, which is the threshold dose for the risk of developing trismus. SPSS software was used and adopted a confidence of 95%. The Kolmogorov-Smirnov normality test, Wilcoxon test, and Spearman correlation were performed. PBMT controls muscular pain and reduced mouth opening limitation in HNC during radiotherapy. Further studies are needed to evaluate the preventive capacity of PBMT protocols for RT trismus-related HNC.

Plan robustness and RBE influence for proton dose painting by numbers for head and neck cancers

PURPOSE

To investigate the feasibility of dose painting by numbers (DPBN) with respect to robustness for proton therapy for head and neck cancers (HNC), and to study the influence of variable RBE on the TCP and OAR dose burden.

METHODS AND MATERIALS

Data for 19 patients who have been scanned pretreatment with PET-FDG and subsequently treated with photon therapy were used in the study. A dose response model developed for photon therapy was implemented in a TPS, allowing DPBN plans to be created. Conventional homogeneous dose and DPBN plans were created for each patient, optimized with either fixed RBE = 1.1 or a variable RBE model. Robust optimization was used to create clinically acceptable plans. To estimate the maximum potential loss in TCP due to actual SUV variations from the pre-treatment imaging, we applied a test case with randomized SUV distribution.

RESULTS

Regardless of the use of variable RBE for optimization or evaluation, a statistically significant increase (p < 0.001) in TCP was found for DPBN plans as compared to homogeneous dose plans. Randomizing the SUV distribution decreased the TCP for all plans. A correlation between TCP increase and variance of the SUV distribution and target volume was also found.

CONCLUSION

DPBN for protons and HNC is feasible and could lead to a TCP gain. Risks associated with the temporal variation of SUV distributions could be mitigated by imposing minimum doses to targets. The correlation found between TCP increase and SUV variance and target volume may be used for patient selection.

An umbrella review exploring the effect of radiotherapy for head and neck cancer patients on the frequency of jaws osteoradionecrosis

OBJECTIVE

Efforts have been made to reduce epidemiological indicators of osteoradionecrosis in patients with head and neck cancer over recent years. This umbrella review aims to synthesize the information of the systematic reviews/meta-analyses investigating the effect of radiotherapy in patients with head and neck cancer on the frequency of osteoradionecrosis and to identify and analyze the gaps in current scientific literature.

MATERIAL AND METHODS

A systematic review of systematic reviews with and without meta-analysis of intervention studies was conducted. Qualitative analysis of the reviews and their quality evaluation were performed.

RESULTS

A total of 152 articles were obtained, and ten of them were selected for the final analysis, where six were systematic reviews and four were meta-analysis. According to the guide Assessing the Methodological Quality of Systematic Reviews (Amstar), eight articles included were of high quality and two of medium quality. These descriptive systematic reviews/meta-analyses included a total of 25 randomized clinical trials, showing that radiotherapy has positive effects on the frequency of osteoradionecrosis. Even though a reduction in the incidence of osteoradionecrosis was observed back in the history, in systematic reviews with meta-analysis, overall effect estimators were not significant.

CONCLUSIONS

Differential findings are not enough to demonstrate that there is a significant reduction in the frequency of osteoradionecrosis in patients with head and neck cancer treated by radiation. Possible explanations are related to factors such as the type of studies analyzed, indicator of irradiated complication considered, and specific variables included in the analysis. Many systematic reviews did not address publication bias and did identify gaps in knowledge that require further clarification.

Backscatter from therapeutic doses of ionizing irradiation does not impair cell migration on titanium implants in vitro

OBJECTIVE

The influence of radiation backscatter from titanium on DNA damage and migration capacity of human osteoblasts (OBs) and mesenchymal stem cells (MSCs) may be critical for the osseointegration of dental implants placed prior to radiotherapy. In order to evaluate effects of radiation backscatter, the immediate DNA damage and migration capacity of OBs and MSCs cultured on titanium or plastic were compared after exposure to ionizing irradiation.

MATERIALS AND METHODS

Human OBs and MSCs were seeded on machined titanium, moderately rough fluoride-modified titanium, or tissue culture polystyrene, and irradiated with nominal doses of 2, 6, 10, or 14 Gy. Comet assay was performed immediately after irradiation, while a scratch wound healing assay was initiated 24 h post-irradiation. Fluorescent live cell imaging documented the migration.

RESULTS

DNA damage increased with higher dose and with backscatter from titanium, and MSCs were significantly more affected than OBs. All doses of radiation accelerated the cell migration on plastic, while only the highest dose of 10 Gy inhibited the migration of both cell types on titanium.

CONCLUSIONS

High doses (10 Gy) of radiation inhibited the migration capacity of both cell types on titanium, whereas lower doses (2 and 6 Gy) did not affect the migration of either OBs or MSCs.

CLINICAL RELEVANCE

Fractionated doses of 2 Gy/day, as distributed in conventional radiotherapy, appear not to cause severe DNA damage or disturb the migration of OBs or MSCs during osseointegration of dental implants.

Oral Mucosa in Cancer Patients-Putting the Pieces Together: A Narrative Review and New Perspectives

The oral mucosa is a key player in cancer patients and during cancer treatment. The increasing prevalence of cancer and cancer-therapy-associated side effects are behind the major role that oral mucosa plays in oncological patients. Oral mucositis is a debilitating severe complication caused by the early toxicity of chemo and/or radiotherapy that can restrict treatment outcome possibilities, even challenging a patient's survival. It has been referred to as the most feared cancer treatment complication. Predictive variables as to who will be affected, and to what extent, are still unclear. Additionally, oral mucositis is one of the sources of the increasing economic burden of cancer, not only for patients and their families but also for institutions and governments. All efforts should be implemented in the search for new approaches to minimize the apparently ineluctable outburst of oral mucositis during cancer treatment. New perspectives derived from different approaches to explaining the interrelation between oral mucositis and the oral microbiome or the similarities with genitourinary mucosa may help elucidate the biomolecular pathways and mechanisms behind oral mucosa cancer-therapy-related toxicity, and what is more important is its management in order to minimize treatment side effects and provide enhanced cancer support.

Enhancement in the Therapeutic Efficacy of In Vivo BNCT Mediated by GB-10 with Electroporation in a Model of Oral Cancer

Boron neutron capture therapy (BNCT) combines preferential tumor uptake of ¹⁰B compounds and neutron irradiation. Electroporation induces an increase in the permeability of the cell membrane. We previously demonstrated the optimization of boron biodistribution and microdistribution employing electroporation (EP) and decahydrodecaborate (GB-10) as the boron carrier in a hamster cheek pouch oral cancer model. The aim of the present study was to evaluate if EP could improve tumor control without enhancing the radiotoxicity of BNCT in vivo mediated by GB-10 with EP 10 min after GB-10 administration. Following cancerization, tumor-bearing hamster cheek pouches were treated with GB-10/BNCT or GB-10/BNCT + EP. Irradiations were carried out at the RA-3 Reactor. The tumor response and degree of mucositis in precancerous tissue surrounding tumors were evaluated for one month post-BNCT. The overall tumor response (partial remission (PR) + complete remission (CR)) increased significantly for protocol GB-10/BNCT + EP (92%) vs. GB-10/BNCT (48%). A statistically significant increase in the CR was observed for protocol GB-10/BNCT + EP (46%) vs. GB-10/BNCT (6%). For both protocols, the radiotoxicity (mucositis) was reversible and slight/moderate. Based on these results, we concluded that electroporation improved the therapeutic efficacy of GB-10/BNCT in vivo in the hamster cheek pouch oral cancer model without increasing the radiotoxicity.

Efficacy of mesenchymal stem cell therapy in rodent models of radiation-induced xerostomia and oral mucositis: a systematic review

BACKGROUND

Radiation-induced xerostomia and oral mucositis are serious complications of radiation therapy for head and neck cancers. Current treatment options have limited efficacy. Mesenchymal stem cell (MSC) therapy has shown promising results in supporting the restoration of glandular secretion function and the regeneration of damaged tissues. This study aim to (1) assess the quality of evidence for MSCs treatment in rodent models of radiation-induced oral complications and (2) determine whether MSCs can improve the therapeutic effect of radiation-induced oral mucositis.

METHODS

Intervention studies using MSCs in rodent models were comprehensively retrieved in the Pubmed, Medline, Embase, Web of Science, and Cochrane library databases on June 1, 2022. The quality of all in vivo experiments was assessed using SYRCLE, and this article is written following the PRISMA guidelines.

RESULTS

A total of 12 studies were included in this systematic review. The study found that in animal models of radiation-induced xerostomia, MSCs could increase salivary protein secretion, improve SFR, shorten the salivary lag time, anti-apoptosis, etc. In animal models of radiation-induced oral mucositis, MSCs improve the micromorphology and macromorphology of RIOM. Moreover, the effect of MSCs on the modification of ulcer duration and latency may be related to the time of MSCs transplantation but further studies are needed.

CONCLUSION

The results of our systematic review suggest that MSCs appeared to be effective in the treatment of radiation-induced xerostomia and oral mucositis.

Prevention of radiotherapy-related oral mucositis with zinc and polyherbal mouthwash: a double-blind, randomized clinical trial

BACKGROUND

A significant percentage of head and neck cancer (HNCs) patients receiving RT experience oral mucositis (OM). This study aimed to evaluate the effect of the polyherbal (containing chamomile, peppermint oil, Aloe vera, and honey) and zinc mouthwashes in comparison to the control (chlorhexidine) and placebo groups for prevention of radiation-induced OM.

METHODS

This study was a double-blinded randomized clinical trial, conducted on 67 patients with HNCs undergoing radiotherapy. The eligible participants were randomized to receive either one of the following; zinc sulfate, polyherbal, chlorhexidine (Vi-one 0.2% CHX), or placebo mouthwash for 6 weeks. Follow-up evaluation of oral hygiene and the checklists of OM and the intensity of pain were filled out according to WHO assessment tool, Oral Mucositis Assessment Scale (OMAS), and Visual Analog Scale (VAS) in all the participants weekly for seven consecutive weeks.

RESULTS

The results of present clinical trial demonstrated that the use of either zinc sulfate or polyherbal mouthwash significantly reduced the scores of OM and the severity of pain during weeks 2 to 7 after consumption compared with the CHX or placebo mouthwashes (P < 0.05). According to the post hoc analysis and compared with the placebo, a significantly better result was reported for zinc sulfate and polyherbal mouthwashes at weeks 2 to 7, but not for the CHX mouthwash.

CONCLUSION

This study showed that the use of zinc sulfate or polyherbal mouthwashes is effective in prevention of both OM severity scores and pain related to OM intensity at weeks 2 to 7 following consumption in HNCs patients. Trial registration IRCT20190123042475N1 and IRCT20190123042475N2. Registration date: 2019-06-09, 2019-07-26.

A Prospective Cohort Study Analyzing Radiation-Induced Xerostomia and Quality of Life of Head and Neck Cancer Patients Treated With Intensity-Modulated Radiotherapy and 3D Conformal Radiotherapy Techniques at a Tertiary Cancer Center in Eastern India

Introduction Cancer of the head and neck is one of the most common cancers in India. Radiotherapy (RT) plays a vital role in the management of head and neck cancer both as a curative and adjuvant modality. Xerostomia is the most common acute and late toxicity. Therefore, this study aimed to analyze radiation-induced xerostomia and the quality of life of patients treated with intensity-modulated radiotherapy (IMRT) and three-dimensional (3D) conformal radiotherapy (3DCRT). Objectives We aim to evaluate radiation-induced acute xerostomia both subjectively and objectively at three-month and one-year post-radiotherapy follow-up period in patients who received radiotherapy in conformal technique (IMRT) to the head and neck region and compare it with those who received the 3DCRT technique. We also aim to assess the recovery of salivary flow in the third month post-radiotherapy by measuring the parotid scintigraphy excretion fraction. Materials and methods Forty patients with head and neck squamous cell carcinoma (SCC) were randomly assigned to the IMRT and 3DCRT arms. Xerostomia during radiation and at three-month and one-year post-radiotherapy follow-up was assessed subjectively using the xerostomia-related quality of life (XeQOL) questionnaire and objectively by measuring the salivary flow rate and parotid scintigraphy. Results The result is analyzed using an independent t-test, Mann-Whitney U test, and Fisher's exact test. The analysis showed that patients treated with radiation by IMRT showed better XeQOL scores (43.40±2.326 in IMRT and 52.10±2.573 in 3DCRT, p<0.001) and Eating Assessment Tool-10 (EAT-10) score (27.65±2.796 in IMRT and 33.80±1.936 in 3DCRT, p<0.001) compared to those treated with 3DCRT. Analysis of the excretion fraction (EF%) of parotid scintigraphy depicted improvement in EF% for both right and left parotids in the IMRT arm with statistical significance (for right parotid, 25.22±12.98 in IMRT and 19.60±10.17 in 3DCRT, p=0.136, and for left parotid, 28.03±12.51 in IMRT and 15.35±11.49 in 3DCRT, p=0.0019). The mean rate of flow (ROF) of saliva showed a declining trend during the end of radiotherapy treatment compared to baseline, but the mean ROF of saliva was better in IMRT compared to 3DCRT, and the difference was statistically significant. The ROF of saliva starts improving during the one-year post-radiotherapy follow-up period. Pearson's chi-square test was used to analyze the correlation between mean parotid dose with EF% of parotid scintigraphy, and it showed a negative correlation, which is statistically significant for both 3DCRT and IMRT arms. Conclusion Xerostomia can be reduced by precision radiotherapies such as the parotid-sparing IMRT technique in head and neck cancer patients, hence improving the quality of life.

Validation of Gujarati Version of European Organization for Research and Treatment of Cancer Quality of Life Modules in Head and Neck Cancer Patients of Western India

Head and neck cancer and its treatment had a significant impact on the quality of life. EORTC QLQ-C30 and EORTC QLQ-H&N35 are the two most widely used modules to assess the quality of life among head and neck cancer patients. The aim of the study is to test the reliability and validity of Gujarati version of EORTC QLQ-C30 and QLQ-H&N35module in a clinical setting. Gujarati version of EORTC QLQ-C30 and QLQ-H&N35 was administered to 400 histo-pathologically proven cases of head and neck cancer. For testing the internal consistency (reliability) Cronbach's alpha coefficient was used. The convergent and discriminant validity were explored by using Spearman's correlation coefficient test. Factor analysis was performed to obtain information about loading of the items for each scale. All most all scales of EORTC QLQ-C30 and QLQ-H&N35 showed high internal consistency having Cronbach's alpha coefficient > 0.70. Spearman's correlation coefficient ranges from -0.45 to 0.95 for EORTC QLQ-C30 and 0.42-0.94 for EORTC QLQ-H&N35 showing moderate to good convergent validity. The magnitude of the correlation of each item with its own scale exceeded the correlation with another scale confirming item discriminant validity. The factor analysis resulted in 7 and 11 different components for measuring quality of life for EORTC QLQ-C30 and QLQ-H&N35 respectively. Based on the results obtained it can be concluded that the Gujarati version of both the modules is a reliable and valid tool for measuring quality of life in head and neck cancer patients in clinical settings.

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.

Biofilm formation of Candida isolates from xerostomic post-radiotherapy head and neck cancer patients

Oral candidiasis is a common problem in post-radiation head and neck cancer (HNC) patients. While biofilm formation is a crucial virulence factor for Candida colonization, existing information on biofilm formation capability of Candida in cancer patients is scarce.

OBJECTIVE

To evaluate biofilm formation capability of Candida spp. colonized in xerostomic post-radiotherapy HNC patients.

DESIGN

Candida albicans and non-albicans Candida species were previously isolated from xerostomic post-radiation cancer patients and healthy individuals. Biofilm mass and biofilm metabolic activity were investigated by crystal violet and MTT assays, respectively. Their relationship with clinical parameters was analyzed using Mann-Whitney U and Chi-square tests.

RESULTS

A total of 109 and 45 Candida isolates from 64 cancer patients and 34 controls, respectively, were evaluated. Both biofilm mass and metabolic activity of Candida isolates from cancer patients were higher than those from controls. The between-group differences were statistically significant in C. albicans (p < 0.001) for biofilm mass, and in C. tropicalis (p = 0.01) for biofilm metabolic activity. Overall, C. tropicalis was the best biofilm producers in both groups. Additionally, we found that higher biofilm formation among C. albicans was associated with low saliva buffering capacity.

CONCLUSIONS

C. albicans and C. tropicalis isolated from xerostomic post-radiation cancer patients had higher biofilm formation capability than those from healthy individuals. Our findings suggest that, in addition to compromised host factors, higher biofilm formation capability may also contribute to the pathogenesis of oral candidiasis in HNC patients. This novel information potentially adds to proper management for these patients.

Effects of ionizing radiation and different resin composites on shear strength of ceramic brackets: an in vitro study

Introduction:

Head and neck cancer is considered one of the most common types, and its treatment includes radiotherapy, which can trigger side effects and undesirable sequelae in the oral cavity and dental tissues.

Objective:

This study aimed to make an in vitro evaluation of the shear strength and failure mode of ceramic orthodontic brackets bonded with two different composites in enamel submitted to ionizing radiation.

Methods:

After the study was approved by the Research Ethics Committee, 60 healthy human premolars were selected and divided into two groups, based on the absence or presence of ionizing irradiation of the enamel. The fragments were thermocycled and then randomly subdivided into two subgroups, according to the composite used for bonding the ceramic brackets (Inspire Ice - Ormco) to the enamel (n = 15): Transbond XT composite (3M), and Light Bond composite (Reliance). After 24 hours, the specimens were submitted to the shear strength test, and the failure mode was analyzed using a stereomicroscope and confocal microscopy. The shear strength data were submitted to two-way ANOVA, considering a significance level of 5%.

Results:

The groups submitted to radiation presented lower shear strength values (4.48MPa) than those not irradiated (9.23MPa) (p< 0.001), and the tested composites were not statistically different (p= 0.078). Regarding the fracture mode, all the groups presented mostly adhesive fractures.

Conclusion:

It was concluded that ionizing radiation negatively affects the adhesion of ceramic brackets, regardless of the composite used for bonding.

Comparative randomized trial study about the efficacy of photobiomodulation and curcumin antimicrobial photodynamic therapy as a coadjuvant treatment of oral mucositis in oncologic patients: antimicrobial, analgesic, and degree alteration effect

INTRODUCTION

As conventional treatments currently available for mucositis are not considerably effective, there is a need to implement an adjuvant protocol for the treatment of oral mucositis in patients undergoing radiotherapy and chemotherapy.

PURPOSE

To evaluate the effect of photobiomodulation (PBM) and antimicrobial photodynamic therapy (aPDT) mediated by curcumin and blue LED as an adjunct treatment of oral mucositis for oncology patients using chemotherapy and/or radiotherapy.

METHODS

Clinical, randomized study, in a single location, in an oncology service of a general hospital, with a total of 30 patients (over 18 years old) with stable oral mucosa lesions in the process of chemotherapy and/or radiotherapy. The patients were divided into 3 groups: control group (treated with nystatin), PBM group (treated with low-level laser therapy), and the aPDT group (treated with 450-nm blue LED and curcumin photosensitizer).

RESULTS

The results showed, by means of intra-group comparisons, that the two experimental treatments promoted yeast reduction of the genus Candida in the last two evaluations (21 days and 30 days), but not in the first two evaluations (7 days and 14 days). The intra-group comparisons showed that the control and aPDT group showed a significant difference in the degree of mucositis over the four evaluations performed, with the results pointing out that the mucositis worsened in the control group from the 14th day, while reduced in the aPDT group from the 21st day of treatment.

CONCLUSION

A reduction in the degree of mucositis and pain score was observed in the PBM and aPDT groups, with the aPDT group standing out when presenting early clinical improvement in relation to the PBM group and the control group, thus emphasizing its effectiveness within the desired aspects. Regarding the antimicrobial effect, aPDT showed a greater reduction of yeasts of the genus Candida in the tested parameters.

Predictors of severe dysphagia following radiotherapy for head and neck cancer

OBJECTIVE

To investigate if severe dysphagia following radiotherapy for head and neck cancer (HNC) could be predicted by patient and tumor characteristics, feeding tube use, weight factors, jaw opening function, and saliva secretion.

METHODS

Data was collected from 94 HNC patients 6 to 36 months post radiotherapy. Swallowing function was assessed by videofluroscopy (VFS). Severe dysphagia was defined by Penetration Aspiration Scale (PAS) as PAS≥5 or a total score ≤60 on the M. D. Anderson Dysphagia Inventory (MDADI).

RESULTS

Thirty-three patients (35%) had PAS ≥5 and 19 (20%) a MDADI ≤60, that is, presented with severe dysphagia. Univariable logistic regression analysis (UVA) gave that tumor of the tonsil, overweight at time of VFS and each unit increase in Body Mass Index (BMI) predicted less risk of PAS ≥5. Dependency of feeding tube at time of VFS and each month's continued use and weight loss ≥7.5% since treatment to time of VFS predicted increased risk of PAS ≥5. Predictive variables from the UVA of PAS ≥5 (tumor of the tonsil, overweight, and total duration of feeding tube), were analyzed by multivariate logistic regression analysis. All retained power as independent predictors. UVA for MDADI showed that use of feeding tube at time of VFS predicted MDADI ≤60 with the risk increasing each month. Each increasing unit of BMI decreased risk of MDADI ≤60.

CONCLUSION

Long time users of feeding tube and higher weight-loss are at risk of severe dysphagia. This makes collaboration between professionals working with dysphagia an important step in detecting severe dysphagia.Level of Evidence: 3.

Radiotherapy changes the salivary proteome in head and neck cancer patients: evaluation before, during, and after treatment

OBJECTIVES

Salivary glands are affected during radiotherapy in the head and neck region, leading to a reduction in salivary flow and changes its composition. Besides negatively affecting the oral soft tissues, this can also lead to dental impairment. Thus, we evaluated the effect of radiotherapy in the proteomic profile of the saliva in patients with head and neck cancer (HNC).

MATERIALS AND METHODS

HNC patients had their saliva collected before (BRT), during (2-5 weeks; DRT), and after (3-4 months; ART) radiotherapy. Saliva was also collected from healthy volunteers (control; C). Samples were processed for proteomic analysis.

RESULTS

In total, 1055 proteins were identified, among which 46 were common to all groups, while 86, 86, 286, and 395 were exclusively found in C, BRT, DRT, and ART, respectively. Remarkably, alpha-enolase was increased 35-fold DRT compared with BRT, while proline-rich proteins were decreased. ART there was a 16-fold increase in scaffold attachment factor-B1 and a 3-fold decrease in alpha-enolase and several cystatins. When compared with C, salivary proteins of BRT patients showed increases cystatin-C, lysozyme C, histatin-1, and proline-rich proteins CONCLUSION/CLINICAL REVELANCE: Both HNC and radiotherapy remarkably change the salivary protein composition. Altogether, our results, for the first time, suggest investigating alpha-enolase levels in saliva DRT in future studies as a possible biomarker and strategy to predict the efficiency of the treatment. Moreover, our data provide important insights for designing dental products that are more effective for these patients and contribute to a better understanding of the progressive changes in salivary proteins induced by radiotherapy. Graphical abstract.

Late radiation effects in survivors of head and neck cancer: State of the science

Head and neck squamous cell carcinoma is one of the most common neoplasms. Radiotherapy (RT) plays an essential role in the management of such cases. Despite advances in the technique, hyposalivation, xerostomia, dysphagia, trismus, radiation caries, and osteoradionecrosis remain significant late complications of RT. The aim of this narrative review was to summarize and update the main findings related to late side effects of radiotherapy in survivors of head and neck cancer (HNC). Such effects limit the ability to speak, ingest food and medications, and breathe and also exert a negative impact on social well-being and quality of life. This review highlights research in the field for both researchers and clinicians, assisting in the prevention and management of these adverse conditions. The findings can contribute to improving preventive management and multidisciplinary interventions for HNC patients.

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.

ODONTOLOGICAL EFFECTS OF IONIZING RADIATION (review)

BACKGROUND

Odontological effects of ionizing radiation (IR) as a result of radiotherapy, the consequences of accidents at nuclear power plants and industry, individual occupational exposure, etc. deserve significant attention interns of radiation medicine and radiation safety.

OBJECTIVE

to analyze and summarize clinical and experimental data on the odontological radiation effects.

MATERIALS AND METHODS

OBJECT

the pathological changes in the hard tissues of teeth, pulp, periodontium, mucousmembranes of the mouth and jaws due to exposure to IR.

METHOD

search in the PubMed / MEDLINE, Google Scholarabstract medical and biological databases, scientific libraries of the relevant sources of scientific information.

RESULTS

Radiobiological effects of IR due to its direct and indirect action are manifested throughout the period ofodontogenesis and formation of the facial skeleton. Experimental and clinical data (in children and adults) indicatethe increased risk of dental caries, reduction of pain threshold and vascularization of tooth pulp along with its fibrosis and atrophy, periodontal dysfunction, which predispose to a high probability of tooth loss. Abnormalities in theactivity of osteoblasts and cementoblasts of dental periosteum and osteoblasts of alveolar process in combinationwith circulatory disorders due to endothelial cell death, hyalinization, thrombosis and vascular obliteration increasethe risk of jaw osteoradionecrosis. Children who have undergone a prenatal exposure to IR as a result of theChornobyl NPP accident have a premature change of teeth. Deterioration of periodontal tissues and early development of acute and complicated dental caries are typical for children and adults affected by the Chornobyl disaster.

CONCLUSIONS

Summarized data on the effects of radiation exposure under different conditions on teeth primordia(i.e. immature teeth), their formation and eruption in experimental and clinical settings, as well as on the odontological radiation effects in adults are summarized. Condition of the teeth in the Chornobyl NPP accident survivorsis described. Understanding and taking into account the radiobiological odontological effects is necessary in thelight of planning, preparing, and conducting local radiation therapy and developing the standards of radiation safety and measures to protect professionals and the public in the event of possible radiation accidents at the nuclearpower plants and industry facilities.

Assessment of saliva and oral candidiasis levels 12, 24 and 36 months after radiotherapy in patients with head and neck cancer

INTRODUCTION

Hyposalivation is a serious complication during radiotherapy (RT) and it is one of the major risk factors for the presence of candidiasis. The aim of this study was to evaluate the salivary hypofunction during the different stages of RT, analysing its connection with the presence of candidiasis.

MATERIAL AND METHODS

A retrospective study was performed in 83 patients who had been diagnosed with head and neck tumours and who were undergoing RT treatment. Their salivary function was clinically analysed throughout the course of the RT treatment (before, during and after treatment) by means of the whole saliva test (WST), both unstimulated (WST-I) and stimulated (WST-II), and its relationship with candidiasis was evaluated using culture-based methods.

RESULTS

The WST-I before RT was 37.24±17.36mm and the WST-II was 60.70±30.98mm, with 47% of patients testing positive for candidiasis. The prevalence of candidiasis increased up to 55.8% during RT and it returned to similar pre-RT levels at the end of treatment (45.2%). A statistical significant relationship was found between low WST-I and candidiasis in the 1st (13.58 vs 20.78mm), 3rd (18.06 vs 24.36mm), 6th (16.83 vs 24.5) and 12th (16 vs 28.74mm) months after RT; and this relationship was also detected for WST-II in the 1st (24.73 vs 41.26mm) and 3rd (27.71 vs 39.91mm) months after RT. Female sex was identified as an independent associated risk factor for mild hyposalivation before RT (OR=6.50, CI: 95% 1.77-23.93, p=0.005) and glandular hypofunction (OR=3.01, CI: 95% 1.12-8.10, p=0.029).

DISCUSSION

There is a clear relation between hyposalivation and the presence of candidiasis during and after RT. Larger studies must be performed in order to further elucidate this effect.

Is there evidence that radiotherapy for head and neck cancer influences the incidence of dental caries?

Data sources Six databases (MEDLINE, EMBASE, CENTRAL, ProQuest, Scopus and Web of Science) and two trial registries (ICTRP, ClinicalTrials.gov) were searched from their inception to May 2019 using a search strategy developed for OVID (MEDLINE/EMBASE).Study selection This systematic review included observational studies and randomised controlled trials related to the incidence of dental caries in patients with a history of head and neck radiotherapy. In addition, studies in which patients received radiotherapy treatment combined with surgical and/or chemotherapy treatment were also included. Study patients all had their teeth assessed and treated before radiotherapy. The diagnosis of caries may have been clinical and/or radiographic and, patients were followed for at least three months. Only English-language papers were included. Studies involving patients with recurrent cancer or with a repeated course of radiotherapy were excluded.Data extraction and synthesis Studies were selected by two independent reviewers, however, if a consensus could not be reached, a third reviewer was consulted. A total of 847 papers were selected through the search. Only 22 studies met the inclusion criteria. Selected articles included three randomised or quasi-randomised controlled trials and 19 observational studies, of which, seven were retrospective studies. The proportions of patients who developed caries after radiotherapy were pooled using a random-effects model. To inquire the between-study heterogeneity, a chi-square standard test was performed. To determine the degree of heterogeneity in proportions across studies, the I2 statistic was calculated. A funnel plot was built to evaluate the publication bias. To verify the correlation between relevant variables (radiation dose, chemotherapy in addition to radiotherapy, cancer site) and the proportion who developed dental caries, a meta-regression was performed. The STATA version 14 software was used for all statistical analysis.Results In the meta-analysis, the pooled percentage obtained of patients with head and neck cancer who developed dental caries post-radiotherapy, considering 15 included studies, was 29%. However, after excluding six studies on the basis of follow-up greater than two years, the pooled percentage increased to 37%. Furthermore, studies with a higher proportion of patients treated with chemotherapy in addition to radiotherapy (after the exclusion of an outlier), and also studies with a higher mean/median radiotherapy dose exposure, had an increased incidence of dental caries (p = 0.02). However, the results should be considered with caution due to the heterogeneity of the included studies.Conclusions The review showed that there is an incidence of approximately 29% of dental caries in patients with head and neck cancer after radiotherapy and, if considering only patients within 2 years post-radiotherapy, the percentage increases to approximately 37%. However, further studies are needed to allow a better understanding of the various factors related to the development of dental caries in patients with head and neck cancer treated with radiotherapy.

Effect of ionizing radiation and chewing simulation on human enamel and zirconia

PURPOSE

To evaluate the effect of ionizing irradiation on human enamel and zirconia after chewing simulation.

METHODS

Twenty enamel and twenty translucent Yttria-stabilized zirconia (Y-PSZ) specimens were divided in 4 groups: Co (control) - no irradiation on enamel cusps/opposing zirconia slabs; E70 - irradiated (70 Gray) enamel cusps/opposing irradiated enamel slabs; Z70 - irradiated zirconia cusps/opposing irradiated zirconia slabs; EZ70 - irradiated enamel cusps/opposing irradiated zirconia slabs. Cusps were abraded against slabs in a chewing simulator (CS - one million cycles, 80 N, artificial saliva, 37˚C). Wear and roughness of zirconia and enamel were analyzed using a stylus profilometer. The abraded enamel was analyzed by Electron probe micro-analyzer (EPMA) and zirconia was characterized by nanoindentation and X-ray diffraction. One-way analysis of variance (ANOVA) and Tukey test were used for analysis of wear, Repeated Measures and Bonferroni test for roughness, and hardness and modulus values were compared using Wilcoxan Mann Whitney rank sum test (overall 5% significance).

RESULTS

Significantly higher volume loss was presented by cusps in the E70 group (p<0.001). Wear was similar between Co and EZ70 groups. There was no significant effect of irradiation on roughness of enamel or zirconia slabs (p=0.072). Irradiated Y-PSZ slabs had significantly higher hardness and modulus than non-irradiated ones and a 7% increase in m phase content was detected after irradiation.

CONCLUSIONS

The opposing surface characteristics played a more significant role on enamel wear than did ionizing radiation. However, radiation affects Y-PSZ crystalline composition, hardness and modulus of elasticity.

Oral microbial profile in oral cancer patients before and after radiation therapy in a cancer care center - A prospective study

Background:

Head and neck cancer is the sixth most common cancer reported worldwide. In many cases, the level of aggressiveness of therapy adopted in cancer patients may cause the alteration in oral microbiota; the emergence of potential pathogens may cause opportunistic infections in already immune-compromised individuals leading to increases in morbidity and mortality. Hence, this study was conducted to assess the oral microbial profile in oral cancer patients before and after radiotherapy.

Materials and Methods:

A total of 145 oral swabs were collected before radiotherapy (n = 96), 3 months postradiotherapy (n = 25), 6 months postradiotherapy (n = 12) and controls (n = 12). The samples were inoculated into brain–heart infusion broth and later in different media for bacterial isolation. The isolates were subjected to phenotypic characterization by automatic identification system.

Results:

Among the 96 samples studied from the preradiotherapy patient samples, Streptococcus species (n = 28) were the predominant isolate, followed by Staphylococcus species (n = 16), Enterobacter species (n = 6) and Enterococcus species (n = 6). Of the 25 samples studied 3 months after radiotherapy, Klebsiella pneumoniae (n = 4) was isolated and 12 samples studied after 6 months of radiotherapy Candida species (n = 4) and Pediococcus species (n = 3) were isolated. Among the control group (n = 12) screened, Streptococcus acidominimus (n = 3) is the predominant bacteria isolated.

Conclusion:

High prevalence of Streptococcus sp. was found in patients of oral cancer before radiotherapy, while Candida albicans and Klebsiella species and Pediococcus species are the significant pathogens isolated in postradiotherapy cancer patients.

Acoustic diagnosis of elastic properties of human tooth by 320 MHz scanning acoustic microscopy after radiotherapy treatment for head and neck cancer

BACKGROUND

On the elastic profiles of human teeth after radiotherapy for head and neck cancers, generation of dental complications, which may bring several side effects preventing the quality of life, has not well clarified. Thus, we aimed to show the applicability of using 320 MHz Scanning Acoustic Microscopy (SAM) in the evaluation of the tooth damage acoustically at the micrometer level following radiation therapy, and also in the determination of the safe dose limits to impede severe dental damage.

METHODS

This prospective study was performed by SAM employed at 320 MHz by an azimuthal resolution of 4.7 μm resolving enamel and dentin. A total of 45 sound human third molar teeth collected between September 2018 and May 2019 were used for the acoustic impedance measurements pre- and post irradiation. Nine samples for each group (control, 2 Gy, 8 Gy, 20 Gy, 30 Gy and 60 Gy) were evaluated to acquire the acoustic images and perform a qualitative analysis. Scanning Electron Microscopy (SEM) images were obtained to establish a relationship between micromechanical and morphological characteristics of the teeth. Statistical analysis was conducted using the Student t-test succeded by Mann-Whitney U investigation (p < .05), while SEM images were assessed qualitatively.

RESULTS

The analysis included 45 sound teeth collected from men and women 18 to 50 years old. Post irradiation micromechanical variations of human teeth were significant only in the radiation groups of 30 Gy and 60 Gy compared to pre-irradiation group for enamel (7.24 ± 0.18 MRayl and 6.49 ± 028 MRayl; p < 0.05, respectively). Besides, the teeth subjected to radiation doses of 20, 30 and 60 Gy represented significantly lower acoustic impedance values relative to non-irradiated group for dentin (6.52 ± 0.43 MRayl, 5.71 ± 0.66 MRayl and 4.82 ± 0.53 MRayl p < 0.05), respectively.

CONCLUSIONS

These results are evidence for a safe acoustic examination device which may be a useful tool to visualize and follow the safe dose limits to impede severe dental damage through the radiation therapy treatment for head and neck cancers.

Effects of a compound vitamin B mixture in combination with GeneTime® on radiation-induced oral mucositis

Objective

Both compound vitamin B mixtures and GeneTime® have been used in treatment of oral inflammation. This study aimed to assess the therapeutic effects of a compound vitamin B mixture combined with GeneTime® on radiation-induced oral mucositis.

Methods

A total of 100 patients with radiation-induced oral mucositis were randomly divided into a control group (vitamin B alone; n = 50 patients) and an observation group (vitamin B plus GeneTime®, n = 50 patients). Clinical outcomes were compared between the two groups for the following 3 weeks.

Results

The observation group had a significantly greater number of grade 0–I patients and significantly fewer grade II–IV patients than the control group. Among patients in the observation group, a significantly greater number of ulcers healed within 1–2 weeks, compared with those in patients in the control group. Significantly fewer ulcers healed among patients in the observation group at 3 weeks; notably, there were fewer ulcers to heal in the observation group, compared with the control group.

Conclusions

Use of a compound vitamin B mixture combined with GeneTime® exerted obvious therapeutic effects on radiation-induced oral mucositis and markedly shortened ulcer healing time. Therefore, this strategy may be useful in clinical applications.

[Analysis of the risk factors of radiation-induced caries in patients with head and neck cancer]

OBJECTIVE

This study aimed to evaluate the risk factors of radiation-induced caries by using a multiple linear regression equation and to provide the basis for the effective prevention of radioactive caries.

METHODS

A total of 166 patients with head and neck cancer who underwent radiotherapy were selected as subjects. The number of decayed, missing or filled surfaces were recorded. Questionnaire contents included age, sex, radiation dose, and radiotherapy techniques. Multiple stepwise regression analyses were performed to identify the risk factors of radiation-induced caries.

RESULTS

Multiple stepwise regression analyses indicated that the main risk factors of radiation-induced caries were plaque index, radiotherapy techniques, time after radiotherapy, and radiotherapy dose.

CONCLUSIONS

The awareness of dental care and caries treatment should be improved to reduce the occurrence of radiation-induced caries in patients with head and neck cancer. In addition, intensity modulated radiation therapy should be employed to decrease the radiation exposure dose received by teeth.

A study on Evaluation of efficacy of bethanechol in the management of chemoradiation-induced xerostomia in oral cancer patients

Objectives:

Squamous cell carcinoma is the most common oral cancer. Radiotherapy with concomitant chemotherapy is an ideal treatment modality largely used for oral cancers, which precipitates many side effects, of which the most challenging and debilitating side effect is xerostomia. This study aimed to evaluate the efficacy of bethanechol in patients with xerostomia following chemoradiation therapy for oral cancer.

Materials and Methods:

Fifty patients with xerostomia postchemoradiation therapy, aged between 30 and 65 years, were selected based on selection criteria. Thirty patients in the study group were administered 25 mg bethanechol three times daily (TDS) and 20 patients in the control group with placebo capsules. The subjective symptoms of oral dryness were periodically evaluated at baseline, at the end of 1^st, 2^nd and 3^rd weeks using a self-reported questionnaire. Salivary analysis such as whole resting saliva and whole stimulated saliva (WSS) volumes, amylase, pH and sodium potassium ratio were evaluated before and 3 weeks after bethanechol and placebo therapy.

Results:

Twenty-four (80%) patients in bethanechol group and only 2 (10%) patients in control group showed subjective improvement in oral dryness at the end of 3^rd week. A significant difference was found between two groups in whole resting and stimulated saliva volume, pH and amylase. However, there was no statistically significant difference in sodium potassium ratio with insignificant adverse effects after 3 weeks of bethanechol therapy.

Conclusions:

25 mg bethanechol (TDS) has shown subjective improvement in oral dryness in 24 (80%) patients with significant improvement in whole resting and WSS volumes, pH and salivary amylase with insignificant adverse effects.

Products based on olive oil, betaine, and xylitol in the post-radiotherapy xerostomia

AIM

The objective of this study was determining if the use of products based in olive oil, betaine and xylitol are efficacious to decrease the impact of the dry mouth in the quality of life of the patients with xerostomia due to radiotherapy treatment.

BACKGROUND

Following therapeutic irradiation of the head and neck, patients with profound xerostomia have complaints associated with oral dryness, speech, and taste. There is no strong evidence that any topical therapy is effective for relieving the symptom of dry mouth.

MATERIAL AND METHODS

40 patients who had been treated with radiotherapy for head and neck carcinoma and reported symptoms of dry mouth were included in the study. A xerostomia-related quality of life questionnaire, visual analogue scale questionnaire for subjective assessment of salivary dysfunction and salivary flow were reported before and 15 days after the use of topical products based on olive oil, betaina and xylitol.

RESULTS

The four primary quality of life areas demonstrated significantly greater improvement after the use of topical products and all eight VAS items had favourable changes. The reduction of symptoms was statistically significant in 7 of the 8 items. After the use of the products, there were improvements in salivary flow in 45%.

CONCLUSIONS

The use of products based on olive oil, betaine and xylitol, shaped like collutory, toothpaste, gel and spray significantly improved most symptoms and the quality of life limitations produced by dry mouth in patients treated with radiotherapy.

Ameliorative effect of black grape juice on systemic alterations and mandibular osteoradionecrosis induced by whole brain irradiation in rats

PURPOSE

Whole brain irradiation (WBI) causes a variety of secondary side-effects including anorexia and bone necrosis. We evaluated the radiomodifying effect of black grape juice (BGJ) on WBI alterations in rats measuring food and water intake, body weight, hemogram, and morphological and histological mandibular parameters.

MATERIALS AND METHODS

Forty male rats (200-250 g) were exposed to eight sessions of cranial X-ray irradiation. The total dose absorbed was 32 Gy delivered over 2 weeks. Four groups were defined: (i) NG: non-irradiated, glucose and fructose solution-supplemented (GFS); (ii) NJ: non-irradiated, BGJ-supplemented; (iii) RG: irradiated, GFS-supplemented; and (iv) RJ: irradiated, BGJ-supplemented. Rats received daily BGJ or GFS dosing by gavage starting 4 days before, continuing during, and ending 4 days after WBI.

RESULTS

RJ rats ingested more food and water and showed less body weight loss than RG rats during the irradiation period. Forty days after WBI, irradiated animals started losing weight again compared with controls as a consequence of masticatory hypofunction by mandibular osteoradionecrosis (ORN). Osteoclastic activity and inflammation were apparent in RG rat mandibles. BGJ was able to attenuate the severity of ORN as well as to improve white and red blood cell counts.

CONCLUSIONS

Fractionated whole brain irradiation induces mandibular changes that interfere with normal feeding. BGJ can be used to mitigate systemic side-effects of brain irradiation and ORN.

Osseointegration and implant stability of extraoral implants in Göttingen minipigs after irradiation

OBJECTIVES

The aim of this study was to compare the influence of implant surface treatment and irradiation dose on implant stability and osseointegration of 144 extraoral implants in irradiated frontal bone of minipigs.

MATERIAL AND METHODS

144 implants with 3 different surface treatments (machined, etched and HAVD-coated) were implanted in the frontal bone of 16 Göttingen minipigs. Three groups of four pigs received radiation with equivalent doses of 25, 50 and 70 Gy, and one group served as control. Resonance frequency analysis (RFA) was performed recording Implant Stability Quotients (ISQ) at implant placement and 3 months thereafter. Removal torque was measured whilst removing specific implants after 3 months. In addition, the bone-to-implant contact (BIC) was analyzed.

RESULTS

Evaluation of ISQ, BIC-values showed no significant difference between the different surface treatments in irradiated and non-irradiated bone. Removal torque revealed statistically significant differences between machined and HAVD-coated implants in the irradiated bone.

CONCLUSIONS

Implant stability and osseointegration, based on Removal Torque showed significant higher results for the HAVD-coated implants. No significant difference was observed between the irradiated and non-irradiated animals. This study shows that HAVD-coated extraoral implants can potentially be used for craniofacial rehabilitation in non-irradiated and irradiated bone.

Radiation-induced dental caries, prevention and treatment - A systematic review

Treatment of head and neck cancers (HNCs) involves radiotherapy. Patients undergoing radiotherapy for HNCs are prone to dental complications. Radiotherapy to the head and neck region causes xerostomia and salivary gland dysfunction which dramatically increases the risk of dental caries and its sequelae. Radiation therapy (RT) also affects the dental hard tissues increasing their susceptibility to demineralization following RT. Postradiation caries is a rapidly progressing and highly destructive type of dental caries. Radiation-related caries and other dental hard tissue changes can appear within the first 3 months following RT. Hence, every effort should be focused on prevention to manage patients with severe caries. This can be accomplished through good preoperative dental treatment, frequent dental evaluation and treatment after RT (with the exception of extractions), and consistent home care that includes self-applied fluoride. Restorative management of radiation caries can be challenging. The restorative dentist must consider the altered dental substrate and a hostile oral environment when selecting restorative materials. Radiation-induced changes in enamel and dentine may compromise bonding of adhesive materials. Consequently, glass ionomer cements have proved to be a better alternative to composite resins in irradiated patients. Counseling of patients before and after radiotherapy can be done to make them aware of the complications of radiotherapy and thus can help in preventing them.

Physical and adhesive properties of dental enamel after radiotherapy and bonding of metal and ceramic brackets

INTRODUCTION

The increasing success rates for cancer patients treated with radiotherapy and the frequent occurrence of tooth loss during treatment have led to an increased demand for orthodontic treatment after radiotherapy. The aim of this study was to evaluate tooth enamel of irradiated teeth after the bonding and debonding of metal and ceramic brackets.

METHODS

Ten permanent molars were cut into enamel fragments measuring 1 mm(2) and divided into an irradiated group (total dose of 60 Gy) and a nonirradiated group. The fragments were subjected to microshear testing to evaluate whether radiotherapy altered the strength of the enamel. Furthermore, 90 prepared premolars were divided into 6 groups and subgroups (n = 15): group 1, nonirradiated and nonaged; group 2, nonirradiated and aged (thermal cycled); group 3, irradiated and aged; each group was divided into 2 subgroups: metallic and ceramic brackets. After thermal cycling and radiotherapy, the brackets were bonded onto the specimens with Transbond XT (3M Unitek, Monrovia, Calif). After 24 hours, the specimens were subjected to the shear tests. Images of the enamel surfaces were classified using the adhesive remnant index. The composite resin-enamel interface was also evaluated.

RESULTS

Enamel fragments subjected to radiation had lower strength than did the nonirradiated samples (P <0.05). The groups and subgroups submitted to radiation and bonded ceramic brackets had the lowest strength values. Groups 1 and 2 with metallic brackets had less adhesive on the surface, whereas groups 1 and 2 with ceramic brackets and group 3 with both metallic and ceramic brackets had more adhesive on the surfaces. On the images of the composite resin-enamel interface, resin tags were more extensive on irradiated tooth enamel.

CONCLUSIONS

Radiation decreased tooth enamel strength, and the specimens treated with radiotherapy had higher frequencies of adhesive failure between the bracket and the composite resin as well as more extensive tags.

The Effects of Ionizing Radiation on the Oral Cavity

AIM

The aim of this study is to present a literature review on the effects of the ionizing radiation from radiotherapy treatment on dental tissues.

BACKGROUND

Among the effects of increasing global life expectancy and longevity of the teeth in the oral cavity, increasing rates of neoplastic diseases have been observed. One of the important treatment modalities for head and neck neoplastic diseases is radiotherapy, which uses ionizing radiation as the main mechanism of action. Therefore, it is essential for dentists to be aware of the changes in oral and dental tissues caused by ionizing radiation, and to develop treatment and prevention strategies.

RESULTS

In general, there is still controversy about the effects of ionizing radiation on dental structures. However, qualitative and quantitative changes in saliva and oral microbiota, presence of oral mucositis and radiation-related caries are expected, as they represent the well-known side effects of treatment with ionizing radiation. Points that still remain unclear are the effects of radiotherapy on enamel and dentin, and on their mechanisms of bonding to contemporary adhesive materials.

CONCLUSION

Ionizing radiation has shown important interaction with organic tissues, since more deleterious effects have been shown on the oral mucosa, salivary glands and dentin, than on enamel.

CLINICAL SIGNIFICANCE

With the increasing number of patients with cancer seeking dental treatment before and after head and neck radiotherapy, it is important for dentists to be aware of the effects of ionizing radiation on the oral cavity.

Investigation of salivary function and oral microbiota of radiation caries-free people with nasopharyngeal carcinoma

Radiation caries have been reported to be correlated with radiotherapy-induced destruction of salivary function and changes in oral microbiota. There have been no published reports detailing patients who have remained radiation caries-free following radiotherapy for nasopharyngeal carcinoma. The aim of this study was to investigate the relationship between salivary function, oral microbiota and the absence of radiation caries. Twelve radiation caries-free patients and nine patients exhibiting radiation caries following irradiated nasopharyngeal carcinoma were selected. V40, the dose at which the volume of the contralateral parotid gland receives more than 40 Gy, was recorded. Stimulated saliva flow rate, pH values and buffering capacity were examined to assess salivary function. Stimulated saliva was used for molecular profiling by Denaturing Gradient Gel Electrophoresis. Mutans streptococci and Lactobacilli in saliva were also cultivated. There were no significant differences in V40 between radiation caries-free individuals and those with radiation caries. Compared with normal values, the radiation caries-free group had significantly decreased simulated saliva flow rate, while there were no significant differences in the saliva pH value and buffering capacity. Similar results were observed in the radiation caries group. There was no statistical difference in microbial diversity, composition and log CFU counts in cultivation from the radiation caries-free group and the radiation caries group. Eleven genera were detected in these two groups, among which Streptococcus spp. and Neisseria spp. had the highest distribution. Our results suggest that changes in salivary function and in salivary microbiota do not explain the absence of radiation caries in radiation caries-free individuals.

Effects of gamma radiation on hard dental tissues of albino rats: investigation by light microscopy

The present work aims at studying the effect of gamma radiation on the hard dental tissues. Eighty adult male albino rats with weights of about 250 g were used. The rats were irradiated at 0.2, 0.5, 1.0, 2.0, 4.0 and 6.0 Gy whole-body gamma doses. The effects on hard dental tissue samples were investigated after 48 h in histological and ground sections using light microscopy. Areas of acid phosphatase activity were detected using tartrate-resistant acid phosphatase (TRAP) stains. Observation of histological sections revealed disturbance in predentin thickness and odontoblastic layer as the irradiation dose increased. In cementum, widened cementocytes lacunae were occasionally detected even with low irradiated doses. On the other hand, relatively homogenous enamel was detected with darkened areas in enamel surface at doses over than 0.5 Gy. TRAP-positive cells were detected on the surface of the dentin of irradiated groups as well as cementum surface. Minimal detectable changes were observed in ground sections.

Head and neck cancer: causes, prevention and treatment

Although head and neck carcinoma ranks fifth among cancer types, patient survival rates have not changed significantly over the past years.

OBJECTIVE

To determine the risk factors, causes, therapies, and prevention measures for head and neck cancer.

METHOD

Risk factors, causes, therapies, and preventive measures for this disease were searched on databases PUBMED, MEDLINE, and SCIELO.

RESULTS

Alcohol and tobacco are still atop risk factors. Other factors may influence the development of head and neck carcinoma. Surgery is the main treatment option, and the addition of radiotherapy following surgery is frequent for patients in the early stages of the disease. Other therapies target specific genetic molecular components connected to tumor development. Disease preventive measures include smoking cessation, limiting alcohol intake, preventing exposure to tobacco smoke and environmental carcinogenic agents, early detection of infection by HPV, maintaining oral health, good eating habits, and managing stress.

CONCLUSION

Additional research is needed for a more thorough understanding of the development of head and neck carcinomas and to shed light on new ways to improve therapeutic approaches and interventions.

Epidemiology and prevalence of oropharyngeal candidiasis in Spanish patients with head and neck tumors undergoing radiotherapy treatment alone or in combination with chemotherapy

OBJECTIVE

To describe the oropharyngeal candidiasis (OPC) prevalence in Spanish patients with head and neck cancer undergoing radiotherapy, alone or combined with chemotherapy. Secondary objectives were to determine the prevalence of Candida species colonization, and to explore whether different Candida species colonizing the oral cavity and the treatment were associated with a higher prevalence of OPC.

METHODS

This is an observational, cross-sectional, multicentre study, conducted in Spanish radiation oncology units. Patients were diagnosed with head and neck cancer and started a radiotherapy treatment alone or combined with chemotherapy at the moment of their inclusion (N = 92).

RESULTS

The OPC prevalence was 26 %. The identification of colonizing pathogens was performed in 49 patients, and Candida albicans was the dominant yeast (69 %), while non-albicans Candida was only found in 15 patients (31 %). Patients with C. albicans colonization had a significant higher prevalence of OPC compared to patients colonized by non-albicans Candida (p = 0.0273), but no difference was found regarding the OPC prevalence in patients receiving only radiotherapy compared to patients with both radiotherapy and chemotherapy treatments.

CONCLUSIONS

Our data represent a step further in the knowledge of Candida species present in Spanish patients with head and neck tumors under radiation therapy. This is an essential step to manage the prophylaxis and treatment of OPC, since it might lead to severe clinical complications causing treatment interruption and, thus, representing a reduction in anti-tumor efficacy.

Incidence and risk factors for infection in oral cancer patients undergoing different treatments protocols

BACKGROUND

Over the past decade, advances in cancer treatments have been counterbalanced by a rising number of immunosuppressed patients with a multitude of new risk factors for infection. Hence, the aim of this study was to determine risk factors, infectious pathogens in blood and oral cavity of oral cancer patients undergoing different treatment procedures.

METHODS

The present prospective cohort analysis was conducted on the patients undergoing treatment in the radiotherapy unit of Regional Cancer Institute, Pt. B.D. Sharma University of Health Sciences, Rohtak, Haryana, during the period of January 2007 to October 2009. Total 186 patients with squamous cell carcinoma of oral cavity were analyzed in the study. Based on treatment procedures patients were divided into three groups, group I were under radiotherapy, group II under chemotherapy and group III were of radio chemotherapy together. Clinical isolates from blood and oral cavity were identified by following general microbiological, staining and biochemical methods. The absolute neutrophile counts were done by following the standard methods.

RESULTS

Prevalent bacterial pathogens isolated were Staphylococcus aureus, Escherichia coli, Staphylococcus epidermidis, Pseudomonas aeruginosa, Klebsiella pneumonia, Proteus mirabilis, Proteus vulgaris and the fungal pathogens were Candida albicans, Aspergillus fumigatus. The predominant gram negative bacteria, Pseudomonas aeruginosa and Klebsiella pneumonia were isolated from blood of radiotherapy and oral cavity of chemotherapy treated cases respectively. The predominance of gram positive bacteria (Staphylococcus aureus and Staphylococcus epidermidis) were observed in blood of chemotherapy, radio chemotherapy cases and oral cavity of radiotherapy, radio chemotherapy treated cases. Our study also revealed the presence of C. albicans fungi as most significant oral cavity pathogens in radiotherapy and radio chemotherapy cases.

CONCLUSION

Gram positive bacteria and Gram negative were reported from the blood of all the three groups of patients. Oral mucositis played a significant role in oral cavity infection and make patients more prone to C. albicans infection.