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OBJECTIVE: This systematic review investigated the dosimetric parameters used in preclinical studies. STUDY DESIGN: Searches were performed in 3 databases (PubMed, Scopus, and Embase) and gray literature to identify studies for review. In vitro and ex vivo studies that examined the effect of radiation on human permanent teeth were included. The modified Consolidated Standards Of Reporting Trials checklist of items for reporting preclinical in vitro studies was used to assess the risk of bias. RESULTS: In total, 32 studies met the inclusion criteria. The average radiation dose of in vitro studies was 53 (±22) Gy and in ex vivo studies was 69 (±1) Gy. Twenty-two studies used 5 different fractionation schemes. Twenty-two of the included studies did not report the radiotherapy modality of those reporting. Twenty studies used linear accelerators, and 7 used Cobalt-60 with the source-surface-distance of radiation ranging from 1.5 to 100 cm. Distilled water was the storage solution for the dental structure used most commonly. Biases were observed, including small sample sizes, lack of randomization, and blinding processes. CONCLUSION: The dosimetric parameters used in the preclinical studies, including radiation dose, radiotherapy modality, fractionation regime, and the storage solutions used did not support the hypothesis of direct effects of radiation on the dental structure.

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STATEMENT OF PROBLEM: When glass-ceramics are treated with hydrofluoric acid (HF), not only the area of application is affected but also other surfaces. Information regarding the correlation of the dissolution caused by HF and the flexural strength of the ceramic is lacking. PURPOSE: The purpose of this in vitro study was to investigate the effect of HF etching protocols on the flexural strength of 2 glass-ceramics, the correlation of their flexural strength with the internal and lateral dissolution, and the differences in Weibull characteristics concerning the etching protocols. MATERIAL AND METHODS: Specimens (4×12×0.3mm) of leucite-reinforced glass-ceramic-LEU (IPS Empress) and of lithium disilicate-reinforced glass-ceramic-LD (IPS e.max) were prepared. The specimens were divided into 5 groups (n=12) according to etching protocol: control-untreated; hydrofluoric acid (HF) 5% for 20 seconds (HF5%20s); HF5%60s; HF10%20s; and HF10%60s. Flexural strength was evaluated through 3-point bend testing. The fractured specimens were submitted to a morphological and metrical analysis of each pattern (LEU I-IV, LD I-III) on the lateral surface (LS) and of the dissolution areas (µm2) on the internal surface (IS) using a scanning electron microscopy (SEM) and a software program (FIJI). Flexural strength (MPa) values were analyzed by 1-way ANOVA, Bonferroni test, and Weibull and the correlation between flexural strength and dissolution by Pearson correlation coefficient (α=.05). RESULTS: ANOVA revealed that the HF etching protocol was significant (P<.001) for LEU ceramic. When HF10%60s was applied, LEU showed Weibull characteristic strength (σθ) values lower than those of the other protocols. LD showed no difference in σθ and reliability (m) among the groups. The internal dissolution areas concerning LEU had a significant high negative correlation with the flexural strength (r=-0.6; P<.001). LEU-IV on the LS was the only pattern to show a significant decrease in flexural strength (r=-0.3, P<.05). CONCLUSIONS: Special care should be taken when applying hydrofluoric acid on glass-ceramic restorations. Protocols with higher hydrofluoric acid concentrations and longer application times were more related to greater internal areas of dissolution which reduced the flexural strength of leucite ceramics.

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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).

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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.

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OBJECTIVE AND STUDY DESIGN: This narrative review summarizes the current state of art of radiation-related caries (RC), an aggressive disease that affects approximately 30% of post-head and neck radiotherapy (HNRT) patients. RESULTS: RC mainly affects the tooth cervical areas and incisal/cuspal tips and develops 6 to 12 months after HNRT. Early RC signs include black/brownish tooth discoloration and enamel cracks, which progress to enamel delamination, exposing underlying dentin to a highly cariogenic oral environment and rapid tooth destruction/dental crown amputation. As RC advances and renders the tooth nonrestorable, it may lead to osteoradionecrosis spontaneously or upon extraction if the tooth is in a highly irradiated field of the oral cavity. This requires aggressive treatment, which would have a negative impact on a cancer survivor's quality of life and contribute to the incremental cost of cancer care. Chlorhexidine mouth rinses and topical fluoride applications are effective agents used in RC prevention; however, there are no well-established treatment protocols. Once RC progresses, dental restorations should be performed with adhesive materials in association with systematic fluoride application as illustrated in the clinical case presented in this review. Post-HNRT patients should be closely followed up for optimal RC prevention, early diagnosis, and prompt treatment. CONCLUSIONS: Future clinical studies are necessary to establish a contemporary, clinically validated protocol for RC management.

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Radiation-related caries (RRC) is a disease with a high potential for destruction of the dentition, which impairs quality of life in head-and-neck (HN) cancer (HNC) patients who undergo radiotherapy. In light of the recently described "clustering of oral symptoms theory," the present systematic review (PROSPERO CRD42019132709) aims to assess HN and gastrointestinal (GI) symptom clusters among HNC patients and discusses how these indirect effects of cancer therapy play a pivotal role in the pathophysiology of RRC. The search was performed at PubMed, Scopus, and Embase and resulted in 11 studies that met the inclusion criteria. Data extraction was performed with respect to the presence of HN/GI symptom clusters among HNC patients. The methodological data of the studies included were assessed using the MAStARI and GRADE instruments. The most prevalent reported HN symptoms were dysphagia, xerostomia, and pain. Taste alterations and fatigue were also commonly reported by the patients. Loss of appetite and weight loss were regularly reported in the studies, as well as nausea and vomiting. The results of the present study suggest that HNC treatment generates clusters of oral symptoms, leading to dietary changes, impaired oral hygiene, enamel fragility, and a highly cariogenic oral environment, which may impact the risk for RRC. A better understanding of oral symptom clustering could be of considerable clinical significance for the oral health and quality of life of HNC patients. Therefore, contemporary protocols of RRC prevention must take this broader treatment scenario of symptom clusters such as oral side effects into account.

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A 31-year-old woman was referred for the evaluation of persistent lower lip numbness following endodontic treatment of tooth #36. Imaging examinations showed a large amount of radiopaque/hyperdense material spread in an angiographic distribution in the left mandibular body region. Laboratory analyses of tooth #36 and adjacent periapical tissue, surgically extracted in an external Service due to acute pain following endodontic treatment, identified chronic inflammatory reaction and birefringent crystalloid foreign bodies rich in barium and sulphur, leading to the diagnosis of alveolar nerve injury due to accidental extrusion of intracanal dressing material composed of calcium hydroxide [Ca(OH)2 ] paste incorporated with barium sulphate. Clinicians should be aware that Ca(OH)2 when in contact with periapical tissues may lead to persistent toxicities, such as necrosis, pain and paraesthesia. Therefore, injectable Ca(OH)2 systems should be used with caution because they can cause paste extrusion and damage to the lower alveolar nerve.

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OBJECTIVE: This study measured the in vivo temperature of prepared root canal walls during various stages of treatment prior to endodontic postcementation. MATERIALS AND METHODS: One tooth each from five patients requiring endodontic treatment received conventional gutta-percha obturation. The coronal 4 mm of gutta-percha was removed by drilling and the canal wall temperature was measured. A sterile, saline rinse was applied, and another temperature value was recorded. Paper points were placed, and the wall temperature was recorded. A standardized period of 1.5 minute passed, simulating time needed to mix and place the resin cement and post (no resin was placed), after which the final wall temperature was obtained. The tooth was temporized and scheduled for prosthetic reconstruction. A one-way repeated measure analysis of variance (with Tukey's post hoc test) was performed among mean temperature values for each treatment stage (preset α 0.05). RESULTS: Significant temperature differences were found among the treatment stages. Canal space drilling yielded the highest temperature (35.5 ± 0.8°C), while the lowest was obtained after saline rinsing (34.0 ± 0.9°C). The temperature of prepared root canal wall prior to postplacement (34.9 ± 1.2°C) and following paper point drying (34.8 ± 1.1°C) presented intermediate results, with no statistical difference between them. CONCLUSIONS: This study suggested that root canal wall temperature varied during various stages of preparation prior to endodontic post.

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OBJECTIVES: To measure and compare in vivo and in vitro pulp temperature (PT) increase (ΔTEMP) over baseline, physiologic temperature using the same intact upper premolars exposed to the same Polywave® LED curing light. METHODOLOGY: After local Ethics Committee approval (#255,945), local anesthesia, rubber dam isolation, small occlusal preparations/minute pulp exposure (n=15) were performed in teeth requiring extraction for orthodontic reasons. A sterile probe of a temperature measurement system (Temperature Data Acquisition, Physitemp) was placed within the pulp chamber and the buccal surface was sequentially exposed to a LED LCU (Bluephase 20i, Ivoclar Vivadent) using the following exposure modes: 10-s low or high, 5-s Turbo, and 60-s high. Afterwards, the teeth were extracted and K-type thermocouples were placed within the pulp chamber through the original access. The teeth were attached to an assembly simulating the in vivo environment, being similarly exposed while real-time temperature (°C) was recorded. ΔTEMP values and time for temperature to reach maximum (ΔTIME) were subjected to two-way ANOVA and Bonferroni's post-hoc tests (pre-set alpha 0.05). RESULTS: Higher ΔTEMP was observed in vitro than in vivo. No significant difference in ΔTIME was observed between test conditions. A significant, positive relationship was observed between radiant exposure and ΔTEMP for both conditions (in vivo: r2=0.917; p<0.001; in vitro: r2=0.919; p<0.001). CONCLUSION: Although the in vitro model overestimated in vivo PT increase, in vitro PT rise was close to in vivo values for clinically relevant exposure modes.

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BACKGROUND: Radiation-related caries (RRC) is one of the most significant oral toxicities of head and neck radiotherapy (HNRT); however, the potential of radiation to directly cause harmful dentin and pulpal effects and impair response to caries progression is controversial. MATERIAL AND METHODS: Therefore, the aim of this study was to characterize the reactions of the dentin-pulp complex in teeth affected by RRC. Patients and methods: Twenty-two carious teeth extracted from 22 head and neck cancer (HNC) patients were divided into control (conventional caries; n=11) and irradiated (RRC; n=11) groups and paired matched by dental homology, clinical patterns of caries progression following the Post-Radiation Dental Index (PRDI) and microscopic depth of carious invasion. Histopathological characteristics based on morphological hierarchy, cell populations of dental pulp, blood vessels, neural elements, extracellular matrix components, inflammation, patterns of carious invasion and reactionary dentin presence were evaluated by optical light microscopy and histomorphometry. RESULTS: Mean PRDI scores were 3.2 for the control group and 3.8 for the irradiated group. Dentin demineralization patterns were also similar between the groups and the mean depths of demineralization were 1,158.58µm and 1,056.89µm for the control and irradiated groups, respectively. CONCLUSIONS: Pulp histopathological changes and dentin reaction patterns were similar between groups and varied according to the PRDI scores and carious lesions depth. Dentin and pulp reactions are highly preserved in RRC teeth. Key words:Cancer, radiotherapy, radiation-related caries, teeth, pulp.