The effects of radiation on teeth

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

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

Purpose

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

Methods and Materials

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

Results

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

Conclusions

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

Effect of Preirradiation Fluoride Treatment on the Physical Properties of Dentin

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

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

Introduction

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

Materials and methods

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

Results

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

Conclusion

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

Effect of different doses of radiation on morphogical, mechanical and chemical properties of primary and permanent teeth-an in vitro study

Background

Radiotherapy, applied to the head and neck region, can cause radiation side effects such as reduction of saliva and radiation caries. The aim of this study was to perform an in vitro assessment of the effects of radiation therapy on the morphological, mechanical, and chemical properties of primary and permanent teeth.

Methods

One hundred four extracted human teeth (52 impacted wisdom teeth, 52 primary molar teeth) were used. The teeth were divided into two parts in the mesiodistal direction. Of the 98 teeth, the vestibular sections were used for the vickers analysis and lingual sections were used for the Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) analysis. The teeth in the experimental group were fixed to wax models. Each model had an equal number of teeth (n = 7). The doses were applied to the teeth for 6 weeks; 5 week days and 2Gy daily. After the radiotherapy was conducted weekly, a wax model was taken from radiation reception. Along with the elemental contents (Na, K, Mg, P, and Ca) of the teeth, enamel and dentin microhardness was evaluated, and SEM analyzes were performed on 6 teeth.

Results

Radiation caused a decrease in microhardness of enamel and dentin (p < 0.05). In the elemental analysis by ICP-OES, it was observed that there were decreases in all elements after 60Gy compared to the control group (p < 0.05). In the experimental groups, amorphous structures were encountered in SEM images.

Conclusions

Radiation has negative effects on the teeth structure and additional studies are needed in this regard. This study indicates that radiotherapy patients are at a higher risk for dental caries.

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.

The effect of radiation therapy on the mechanical and morphological properties of the enamel and dentin of deciduous teeth--an in vitro study

Purpose

To evaluate the effects of radiation therapy on deciduous teeth.

Materials and methods

The enamel and dentin microhardness (n = 12) was evaluated at 3 depths, both before (control) and after each 10 Gy of irradiation and up to a dose of 60 Gy. The morphology was evaluated via scanning electron microscopy (SEM) (n = 8). The data were analyzed using a two-way analysis of variance (ANOVA) and Tukey’s test (α = 5%).

Results

The enamel microhardness, as a whole, increased (p < 0.05) after a dose of 60 Gy (211.4 KH), mostly in the superficial enamel. There was a significant difference between the values of nonirradiated dentin microhardness (28.9 KH) compared with dentin that was irradiated with doses of 10 Gy (23.8 KH), 20 Gy (25.6 KH), 30 Gy (24.8 KH), and 40 Gy (25.7 KH) (p < 0.05). There was no difference between nonirradiated dentin and dentin irradiated with 60 Gy (p > 0.05). The highest mean value of microhardness (29.9 KH) (p < 0.05) was found in the middle dentin. The groups that were irradiated with doses of 30 and 60 Gy exhibited greater surface changes in their enamel and dentin compared with the nonirradiated groups for all regions, exhibiting an amorphous surface upon increase of the irradiation doses.

Conclusions

The enamel microhardness increased at a dose of 60 Gy, whereas the value of the dentin microhardness did not change. A progressive disruption of enamel and dentin morphology was found with the increased radiation dose.

[Radiation-related caries: etiology and possible preventive strategies. What should the radiotherapist know?]

BACKGROUND

After radiation treatment of head-and-neck cancer, the impairment of patient's quality of life still remains an issue. After completion of the treatment course, a substantial number of patients develop so-called radiation caries. In addition, almost 50% of all cases of infectious osteoradionecrosis (iORN) of the jaws are directly associated with radiation caries. This review addresses our current knowledge on the etiology and pathogenesis of radiation caries including possible preventive strategies.

MATERIALS AND METHODS

A PubMed search using the terms "radiation caries" ("radiation related caries", "radiation related damage to dentition") and "radiogenic caries" ("postradiation caries", "dental complications and radiotherapy") was performed. The analysis of its content focused on the etiology, the pathogenesis, and the available knowledge on prophylaxis as well as treatment of radiation caries.

RESULTS

For this review, 60 publications were selected. As main causal factors for radiogenic caries, either indirect impairment, resulting from alterations in the oral environment (e.g., radiation-induced xerostomia) or direct radiation-induced damage in teeth hard tissues are discussed. Radiation caries remains a lifelong threat and, therefore, requires permanent prevention programs.

CONCLUSION

To enable optimal medical care of the patients during the time course of radiotherapy as well as afterwards, close interdisciplinary cooperation between radiotherapists, oral surgeons, otorhinolaryngologists, and dentists is absolutely essential.

Effects of therapy on dentofacial development in long-term survivors of head and neck rhabdomyosarcoma: the memorial sloan-kettering cancer center experience

PURPOSE

To describe potential effects of multimodality therapy on dental and facial development in long-term survivors of head and neck rhabdomyosarcoma.

PATIENTS AND METHODS

The medical records of all patients aged 20 years or less presenting between 1985 and 1996 with a diagnosis of rhabdomyosarcoma and treated by protocol were reviewed. Head and neck rhabdomyosarcoma patients who were followed in the Dental Service and were alive and free of disease with at least a 5-year follow-up were included in the review. Ten patients satisfied the inclusion criteria and form the basis of this report. The median age at diagnosis of the 10 patients was 4.3 years (range 10 months to 19.5 years). All patients were treated with chemotherapy, two patients underwent surgery, and all but one patient received external beam radiation therapy.

RESULTS

Clinical or radiographic dentofacial abnormalities were observed in 8 of the 10 (80%) patients. Abnormalities included enamel defects, bony hypoplasia/facial asymmetry, trismus, velopharyngeal incompetency, tooth/root agenesis, and disturbance in root development. Bony hypoplasia and disturbance in root formation were the most common findings.

CONCLUSIONS

Multimodality therapy for head and neck rhabdomyosarcoma can result in dentofacial abnormalities that affect the patient's quality of life. The care of the long-term survivor requires a multidisciplinary approach, including early involvement of the dental team.

Protective effect of amifostine on dental health after radiotherapy of the head and neck

PURPOSE

The cytoprotective agent amifostine has been shown to reduce the radiation-induced acute and chronic xerostomia in head and neck cancer patients. The purpose of this study was to evaluate whether or not amifostine also reduces the incidence of dental caries associated with the radiation-induced xerostomia.

METHODS AND MATERIALS

The dental status before and 1 year after radiotherapy was retrospectively compared in 35 unselected patients treated as part of the prospective randomized and multicenter open-label Phase III study (WR-38) at the University Hospitals of Heidelberg, Freiburg, and Erlangen. The WR-38 study compared radiotherapy in head and neck cancer with and without concomitant administration of amifostine.

RESULTS

Patient and treatment characteristics (particularly the radiation dose and percentage of parotids included in the treatment volume) were equally distributed between the patients who received (n = 17) or did not receive (n = 18) amifostine. Fifteen patients of the amifostine group showed no deterioration of the dental status 1 year after radiotherapy as compared to 7 patients who did not receive the cytoprotector (p = 0. 015, two-tailed Fisher exact test).

CONCLUSION

Our data suggest a protective effect of amifostine on the dental health after radiotherapy of the head and neck. The dental status should be used as a primary endpoint in future studies on amifostine.

[New evidence for the etiology of so-called radiation caries. Proof for directed radiogenic damage od the enamel-dentin junction]

AIM

In spite of a great number of relevant studies the etiology of radiation induced caries still is discussed in controversy: The assumption of direct radiation induced lesions in the hard tissue is in contrast to an indirect pathogenesis mediated via radio-xerostomia.

METHODS

A systematic study is presented, comparing teeth with a manifest radiation caries (group 1, about 60 Gy, long interval to the extraction) and clinically caries free teeth (group 2, about 30 Gy, short interval) with tooth specimens after an experimental enoral (in situ) irradiation (60 Gy, group 3) and after in vitro irradiation (500 to 2,500 Gy, group 4). 60Co was the irradiation source. Sound teeth were used as a standard (group 5). For non destructive visualisation of subsurface histotomograms by confocal laser scanning microscopy (CLSM) teeth were either used as fresh sections or as Technovit embedded thin slices (sawing grinding technique).

RESULTS

Tooth samples from radiotherapy patients (cancer therapeutic doses, long interval before extraction; group 1) showed three characteristic changes: 1, rarefcation of the branching (ramification) of odontoblast processes near the junction, 2. dentine tubules end in front of the interface to the hard tissue and 3, in dentine the interface is characterised by an zone (about 10 microns wide) of low intensity of the remitted light.

CONCLUSIONS

The obliteration of the dentine tubules, preceded by a degeneration of the odontoblast processes, is obviously the result of a direct radiogenic cell damage with hampered vascularisation and metabolism particularly in the area of the terminations of the odontoblast processes. The deficit in metabolism combined with a latent damage of the parenchyma (hypo-remitting zone) is evidence for the functional symptoms (subsurface caries). The prerequisite for the micromorphological manifestation of this direct irradiation damage is a vital tooth and in consequence cannot be simulated in situ or in vivo.

Irradiation effects on microhardness of fluoridated and non-fluoridated bovine dentin

The objective of this study was to evaluate the effects of irradiation on microhardness of dentin. Dentin blocks from the cervical region of bovine incisors were treated as follows: (1) no irradiation; (2) irradiation of specimens up to 60 Gy (2 Gy/day, 5 days/week); (3) no irradiation, but fluoridation of specimens for 5 min/d; (4) irradiation of specimens and daily fluoridation. Knoop hardness number (KHN) of the control specimens was 62.63+/-14.75 (mean+/-SD). This was significantly different from the irradiated dentin samples (8.74+/-2.59 KHN). Hardness of the fluoridated dentin specimens was 11.19+/-1.95 KHN in the non-irradiated group and 10.03+/-2.76 KHN in the irradiated groups, respectively. Within the limitations of an in vitro study, it is concluded that dentin is severely affected by irradiation. This could be an explanation for the frequently observed side-effects of irradiation like loss of enamel, gap formation at the amelodentinal junction, and caries of the cervical region. Fluoridation with acidic gels decreases microhardness of dentin surface, and does not prevent softening due to radiation, when saliva is absent.

[Confocal laser scanning microscopy (CLSM): histotomography of altered dental hard tissue in pathological mouth cavity ecology]

There is no consensus regarding the aetiology of radiation-induced caries. Lesion formation is assumed to originate either from direct radiogenic damage of the hard tissue or from the indirect effects correlated with radioxerostomia. A comparative study is presented of sound teeth (group 1), teeth with documented radiation caries (group 2), teeth after in situ radiation (group 3): 60 Gy, fractionated) and teeth after in vitro radiation (group 4: 500-2500 Gy). Radiations were carried out with a 60Co source. The dentoenamel junction was studied with confocal laser scanning microscopy (CLSM). Axial sections of the teeth were used either fresh or embedded in Technovit (sawing-grinding technique). Under these conditions subsurface areas of the sections can be visualized non-destructively. Characteristic modifications could be observed only after in vivo radiotherapy (group 2): (1) the ramifications near the junction are rare, (2) the dentine tubuli end before the limits of the hard tissue and (3) the remittance of light in reduced in a 10-microns-wide zone along the dentoenamel junction. The obliteration of the dentine tubuli following degeneration of the odontoblast processes obviously is the result of the direct radiogenic cell damage, with reduced metabolism particularly in the area of the ends of the odontoblasts. The metabolism deficit mediates parenchymal damage (zone of reduced light remittance), explaining the functional symptom of undermining caries. The micromorphological manifestation of this direct radiation damage obviously requires the vital tooth and therefore cannot be observed after in vitro and in situ irradiation.

Absence of salivary glands in children with rampant dental caries: report of seven cases

Seven cases of absence of two or more salivary glands in children are presented. In six of the cases the condition was congenital and in one it was the result of surgery to the submandibular ducts. The patients had been referred for treatment of rampant dental caries and were reviewed for periods ranging from 6 months to 15 years 9 months. The diagnosis of absence of salivary glands was based on careful inspection and palpation of the duct and duct orifice of each gland. One patient had dry lips and three had dry mouths, but none complained of excessive thirst or difficulty with mastication or swallowing. All the patients had very poor oral hygiene and rampant dental caries. The presence of carious lesions in mandibular incisors, particularly when their severity exceeds those present elsewhere in the mouth, should alert the clinician to the possibility that salivary glands may be absent.

Dental abnormalities in long-term survivors of head and neck rhabdomyosarcoma

To define the long-term dental sequelae of therapy for childhood rhabdomyosarcoma of the head and neck, and to identify factors in their development, we retrospectively reviewed the serial panoramic radiographs and clinical records of 22 survivors of head or neck rhabdomyosarcoma who had been followed for at least 5 years. Patients were divided into four groups based upon age at the time of therapy and three groups based upon radiation doses. All patients had received similar multiagent chemotherapy. Dental sequelae of oncotherapy occurred in over half of the long-term survivors of head and neck rhabdomyosarcoma. The abnormalities comprised root stunting in 54%, microdontia in 23%, and hypodontia in 50% of patients; 36% had multiple abnormalities. Microdontia and multiple abnormalities were more prevalent in patients treated at the earliest age, and abnormalities tended to be more prevalent with increasing doses of radiation. Five patients (23%) developed severe cosmetic and/or functional sequelae necessitating surgical and/or orthodontic intervention. The high frequency of dental sequelae we observed suggests that meticulous long-term dental and radiographic follow-up are needed. Early detection and treatment of the complications of therapy will expedite their correction and minimize morbidity.

Radiation-induced hypoplasia of the teeth and mandible. A case report

Hypoplasia of the mandible and teeth is reported in a 4-year-old boy who had cystic hygroma. At age 7 months he had been treated with 60Co-gamma-radiation (24 Gy to the head and neck, 45 Gy to the mediastinum) followed by surgery. Panoramic and periapical radiographs showed hypoplasia of the roots of the primary canines, molars, and permanent teeth and no evidence of tooth germs. The patient was followed up to age 13 years.

Induction of cleft palate by gamma-irradiation of prenatal CD-1 mice

Fetuses of pregnant mice exposed to whole body gamma-irradiation (400 rads) on the 12th gestational day were compared with control fetuses to assess the effect of radiation on palatogenesis. Experimental and control groups were sacrificed on day 18 of gestation. The fetuses were removed via laparotomy and counted to determine the litter size. Animals were decapitated and the maximum head height, width, and circumference recorded. For light microscopic examination of palatogenesis, heads were fixed in Bouin's solution and prepared for paraffin sectioning and staining with hematoxylin and eosin. A significant reduction in litter size (p < .0025) and head measurements (p < .005) of irradiated fetuses was observed when compared to those of the control group. Histologic examination of serial coronal sections demonstrated that 100% of the experimental fetuses had palatal clefts. It was concluded that gamma-rays have adverse effects on the litter size, head measurements, and palatal closure of mouse fetuses.

Effect of gamma-irradiation on prenatal development of the tongue in CD-1 mice

Development of the tongue in murine fetuses, in which the dams were exposed to whole body gamma-irradiation (400 rads) on the 12th day postcoitum, was studied and compared with unirradiated controls. Experimental and control groups were killed on day 18 of gestation and the fetuses were removed via laparotomy. The fetal heads were excised, fixed in Bouin's solution, prepared for paraffin sectioning, and stained with hematoxylin and eosin for light microscopic examination. Histologic examination of serial coronal sections demonstrated that all of the experimental fetuses possessed malformed, poorly developed tongues, when compared to those of the control group. It was concluded that gamma-irradiation has an adverse effect on tongue development in mouse fetuses.

Effect of gamma-irradiation on prenatal development of the nasal septal cartilage in CD-1 mice

The effects of gamma-rays on nasal septum development in CD-1 mouse fetuses subsequent to irradiation of their mothers were studied. Pregnant CD-1 mice exposed to 400 rads of whole body gamma-irradiation 12 days after gestation were sacrificed on day 18, post coitum. The fetuses were removed via laparotomy and analyzed. Data on head dimensions, including head height, width, and circumference were recorded. Fetal heads were then routinely prepared for histologic examination of the developing nasal septal cartilage. Analysis of data revealed significant reduction in litter size (p < .0025) and head measurements (p < .0005) of irradiated animals. Histologically, the nasal septa of irradiated fetuses had retarded growth, were less differentiated, and smaller than those of control mice. Results suggest that gamma-irradiation has detrimental effects on litter and head sizes and may interfere with the cellular maturation process of nasal septal cartilage as well as other structures.

Micrognathia after radiation therapy for childhood facial tumors. Report of two cases with long-term follow-up

As the survival duration and cure rate of children with malignant conditions improve, awareness of long-term side effects is crucial. Two case reports demonstrate long-term changes in dentition and orofacial development in children who had been treated for facial malignant conditions. Changes induced mandibular and maxillary hypoplasia, partial anodontia, microdontia, altered eruption pattern, root stunting, and altered amelogenesis.

Effects of gamma radiation on incisor development of the prenatal albino mouse

Fetuses of pregnant albino mouse exposed to 400 rad of gamma-irradiation, on the 12th gestational day, were compared with unirradiated fetuses to asses the radiation effect on developing incisors. Pregnant animals were sacrificed on day 18 post coitum, and their fetuses were decapitated. Heads were routinely prepared, frontally sectioned, and stained with hematoxylin and eosin. Histologic examination demonstrated that the development of the maxillary and mandibular incisors was retarded in all the experimental fetuses and were in early bell stage, whereas those of the control animals were elaborated their matrices. It was concluded that gamma-irradiation interferes with cytodifferentiation of the enamel organ and dental papilla and subsequently inhibits normal odontogenesis.

Disturbances in dental development after total body irradiation in bone marrow transplant recipients

The dental status of 16 children who had been treated with bone marrow transplantation (BMT) for serious bone marrow diseases was followed for up to 6 years. Several types of disturbances in dental development were observed in children who had been conditioned with total body irradiation (TBI) at 10 Gy before BMT. Thus, impaired root development that caused short V-shaped roots was found in all patients, a complete failure of root development and premature apical closure were found in five patients, enamel hypoplasia was observed in four patients, and microdontia was observed in three patients conditioned with TBI. Patients younger than 6 years of age at BMT exhibited the most severe and extensive dental aberrations. The TBI at 10 Gy appeared to be the major cause of the disturbances found.

Malnutrition and the role of nutritional support for radiation therapy patients

The nutritional status of a tumor patient can be negatively influenced by the local and systemic effects of the malignant tumor (tumor cachexia, anorexia, difficult oral food intake), by the effects of the various antitumoral therapy modalities (surgery, radiotherapy, chemotherapy), and by the complications associated with such modalities (anorexia, nausea, vomiting, mucositis, xerostomia, alterations of the smell and taste sensations, odynophagia, dysphagia, maldigestion, malabsorption, diarrhea, steatorrhea, conditioned aversions, radiogenic late effects), as well as by the psychological reactions of the patient to the real or feared existence of his tumor. The radiation-induced nutritional disorders depend on the tumor localization, the region irradiated, the dose and length of radiotherapy, the fractionation, the volume irradiated, and the combination with other therapeutic modalities ("combined modality therapy"). The acute radiation-induced reactions are usually of limited duration and for this reason tend to interfere with the nutritional status to a lesser extent than the permanent chronic consequences of irradiation. Weight loss and malnutrition tend to develop particularly in patients in whom segments of the gastrointestinal tract are subjected to irradiation. The incidence and severity of deficient nutrition depend not only on the region irradiated (head-neck region, thorax, abdomen, pelvis) but also, and most particularly, on the volume of the digestive tract irradiated. Chemotherapy and radiotherapy combined act very strongly on rapidly proliferating cell populations (skin, mucosa, epithelium of the gastrointestinal tract). In this context, actinomycin D and adriamycin act like real sensitizers, whereas the majority of the other drugs are likely to produce only an additive effect. The first named cytostatics give rise to the so-called recall phenomenon, i.e., the reactivation of latent radiation effects in response to the subsequent administration of the drug. Malnutrition impairs organ function and ultimately results in increased morbidity and mortality. For this reason it has proven mandatory and reasonable that the organism of all tumor patients suffering from malnutrition is provided with the missing essential nutrients (especially amino acids for protein synthesis). This tends to clearly improve the Karnofsky performance status, with a positive effect on response rates, toxicity, and survival rates in retrospective studies.(ABSTRACT TRUNCATED AT 400 WORDS)

Failure of root development of human permanent teeth following irradiation

Complete absence of root formation of the upper incisors, canine and first premolar was reported in a 27-year-old female who had received radiation therapy for a retinal glioma of the right eye at age of 3 years 1 month. Ground and decalcified sections showed no remarkable changes in enamel and dentin of the crowns, but the pulp floor was closed by irregular dentin deposit despite the absence of root formation. The outer surface of the irregular dentin was covered by acellular cementum, and the periodontal membrane was undeveloped. A slight degree of fibrosis was seen in the pulp, but the coronal part of the dentin was lined by odontoblasts. The theory that tooth eruption is caused by the growth of the root is not substantiated by the observation in this case.

Late effects after treatment of twenty children with soft tissue sarcomas of the head and neck. Experience at a single institution with a review of the literature

Twenty children with soft tissue sarcomas of the head and neck, treated at the Children's Hospital of Philadelphia and the Hospital of the University of Pennsylvania from 1972 to 1981, were evaluated for the late deleterious effects of treatment. All patients received radiation therapy and combination chemotherapy with vincristine, dactinomycin, and cyclophosphamide; certain patients also received Adriamycin (doxorubicin). All had ophthalmologic, otologic, growth, and cosmetic evaluations; 15 also had dental and maxillofacial examinations. The median age at diagnosis was 6 years (range, 7 months-13 years). Median follow-up from time of diagnosis was 5.5 years with a minimum of 3 years in all but four patients. The major problems encountered were related to the eyes (xerophthalmia and cataracts), ears (hearing loss), teeth (maleruption and caries), glandular structures (xerostomia, hypopituitarism), and development (craniofacial deformity). It is concluded that children treated for soft tissue sarcomas of the head and neck with combined modality therapy, including radiation enhancers, may show a variety of late treatment-related adversities. These children require close multidisciplinary follow-up for detection of late effects in order that appropriate prophylactic or symptomatic treatment can be instituted to minimize their consequences.

Complications following radiation therapy to the head

A case is presented in which a child who received therapeutic radiation as part of his treatment regimen for rhabdomyosarcoma of the infratemporal and parapharyngeal region demonstrated undesirable sequelae in the dentition and the mandible.

Analysis of endodontic therapy in patients irradiated for head and neck cancer

The outcome of endodontic therapy in 16 patients irradiated for head and neck cancer was studied. Thirty-five postradiation endodontically treated teeth (54 roots) were included in the study. The follow-up period ranged from 6 months to 54 months. At the time of last follow-up, 46 of 54 roots were being maintained. No osteoradionecroses were seen in association with teeth that had been endodontically treated. From this review, it is clear that endodontic therapy is a viable method of treating diseased teeth in patients irradiated for oral neoplasms.

Oral presentations in non-Hodgkin's lymphoma: a review of thirty-one cases. Part III. Six cases in children

This is the third in a series of articles dealing with oral presentations in non-Hodgkin's lymphoma. In this section the authors discuss the clinical and microscopic features of six cases occurring in children, four of which qualified as Burkitt's lymphoma.

The effect of radiotherapy in the treatment of retinoblastoma upon the developing dentition

Two patients who received supervoltage x-ray external beam irradiation for treatment of retinoblastoma by standard techniques showed interference with the root formation of the maxillary deciduous molars and abnormalities of crown and root formation of the permanent maxillary molars. Both patients showed a relative maxillary retrognathism thought to be related to radiation effects on maxillary bone growth. Simulation of lateral radiation portals with subsequent beam shaping using an appropriate block placed in the radiation beam is suggested as a means to eliminate the dental complications of radiation therapy for retinoblastoma.

Alterations of nutritional status: impact of chemotherapy and radiation therapy

The nutritional status of a cancer patient may be affected by the tumor, the chemotherapy and/or radiation therapy directed against the tumor, and by complications associated with that therapy. Chemotherapy-radiotherapy is not confined exclusively to malignant cell populations; thus, normal tissues may also be affected by the therapy and may contribute to specific nutritional problems. Impaired nutrition due to anorexia, mucositis, nausea, vomiting, and diarrhea may be dependent upon the specific chemotherapeutic agent, dose, or schedule utilized. Similar side effects from radiation therapy depend upon the dose, fractionation, and volume irradiated. When combined modality treatment is given the nutritional consequences may be magnified. Prospective, randomized clinical trials are underway to investigate the efficacy of nutritional support during chemotherapy-radiotherapy on tolerance to treatment, complications from treatment, and response rates to treatment. Preliminary results demonstrate that the administration of total parenteral nutrition is successful in maintaining weight during radiation therapy and chemotherapy, but that weight loss occurs after discontinuation of nutritional support. Thus, long-term evaluation is mandatory to learn the impact of nutritional support on survival, disease-free survival, and complication rates, as well as on the possible prevention of morbidity associated with aggressive chemotherapy-radiation therapy.

The effect of irradiation on developing teeth

Although the consequences of ionizing irradiation on adult teeth have been adequately described in the literature, there have been few reports concerning the adverse effects on the developing dentition. A case is presented in which the jaws were irradiated at an early age and it was possible to examine some of the abnormal teeth in detail by using clinical, radiographic, and histologic techniques.

Laser applications in medicine and biology: a bibliography

This bibliography covers the period from 1963 through 1974; 916 references are classified under 23 subject headings. The references are arranged chronologically.