Low-level laser therapy affects dentinogenesis and angiogenesis of in vitro 3D cultures of dentin-pulp complex.

To investigate the effects of gallium-aluminum-arsenide (GaAlAs) diode laser low-level laser therapy (LLLT) on angiogenesis and dentinogenesis of the dentin-pulp complex in a human tooth slice-based in vitro model. Forty tooth slices were prepared from 31 human third molars. Slices were cultured at 37 °C, 5% CO2, and 95% humidity and randomly assigned to one of the following groups: group I: no laser treatment, group II: 660-nm diode laser; energy density = 1 J/cm2, group III: 660-nm diode laser; energy density = 3 J/cm2, group IV: 810-nm diode laser; energy density = 1 J/cm2 and group V: 810-nm diode laser; energy density = 3 J/cm2. LLLT was applied on the third and fifth days of culture. After 7 days, tissues were retrieved for real-time RT-PCR analysis to investigate the expression of VEGF, VEGFR2, DSPP, DMP-1, and BSP in respect to controls. Lower energy density (1 J/cm2) with the 660 nm wavelength showed a statistically significant up-regulation of both angiogenic (VEGF: 15.3-folds and VEGFR2: 3.8-folds) and odontogenic genes (DSPP: 6.1-folds, DMP-1: 3-fold, and BSP: 6.7-folds). While the higher energy density (3 J/cm2) with the 810 nm wavelength resulted in statistically significant up-regulation of odontogenic genes (DSPP: 2.5-folds, DMP-1: 17.7-folds, and BSP: 7.1-folds), however, the angiogenic genes had variable results where VEGF was up-regulated while VEGFR2 was down-regulated. Low-level laser therapy could be a useful tool to promote angiogenesis and dentinogenesis of the dentin-pulp complex when parameters are optimized.

Cell dynamics in Hertwig's epithelial root sheath and surrounding mesenchyme in mice irradiated to the head.

OBJECTIVE: To investigate the mechanisms that cause damage to root formation as a result of irradiation to the mouse head, morphological changes in molar dental roots and cell dynamics in Hertwig's epithelial root sheath (HERS), and surrounding mesenchymal tissue were examined. MATERIALS AND METHODS: To perform the experiments, 5-day-old C57BL/6 mice were randomly divided into three groups: the control group (0 Gy) and irradiated groups (10 and 20 Gy). Micro-CT analysis, HE staining, immunohistochemistry analysis, and TUNEL assay were then performed. RESULTS: Roots in irradiated mice were dose-dependently shorter than those of control mice. Cells located outside the root dentin, with abnormal morphology in irradiated mice, were positive for an odontoblast marker. HERS fragmentation occurred earlier in irradiated mice than in control mice, and HERS was trapped by the calcified apical tissue. A dose-dependent reduction in the number of proliferating cells within the apical dental pulp and periapical periodontal ligament surrounding HERS was observed in irradiated mice. Apoptotic cells in the dental pulp and periodontal ligament surrounding HERS were hardly seen. CONCLUSIONS: These results indicate that the early disappearance of HERS and the proliferative suppression of the surrounding mesenchymal cells, which was induced by irradiation, caused dental root malformation.

Effect of Low-Level Diode Laser and Red Light-Emitting Diode on Survival and Osteogenic/Odontogenic Differentiation of Human Dental Pulp Stem Cells.

Background: This investigation set out to compare the impacts of low-level diode laser (LLDL) and red light-emitting diode (LED) on the survival of human dental pulp stem cells (hDPSCs) and osteogenic/odontogenic differentiation. Methods and materials: In this ex vivo experimental study, the experimental groups underwent the irradiation of LLDL (4 J/cm2 energy density) and red LED in the osteogenic medium. Survival of hDPSCs was assessed after 24 and 48 h (n = 9) using the methyl thiazolyl tetrazolium (MTT) assay. The assessment of osteogenic/odontogenic differentiation was conducted using alizarin red staining (ARS; three repetitions). The investigation of osteogenic and odontogenic gene expression was performed at two time points, specifically 24 and 48 h (n = 12). This analysis was performed utilizing real-time reverse-transcription polymerase chain reaction (RT-PCR). The groups were compared at each time point using SPSS version 24. To analyze the data, the Mann-Whitney U test, analysis of variance, Tukey's test, and t-test were utilized. Results: The MTT assay showed that LLDL significantly decreased the survival of hDPSCs after 48 h, compared with other groups (p < 0.05). The qualitative results of ARS revealed that LLDL and red LED increased the osteogenic differentiation of hDPSCs. LLDL and red LED both upregulated the expression of osteogenic/odontogenic genes, including bone sialoprotein (BSP), alkaline phosphatase (ALP), dentin matrix protein 1 (DMP1), and dentin sialophosphoprotein (DSPP), in hDPSCs. The LLDL group exhibited a higher level of gene upregulation (p < 0.0001). Conclusions: The cell survival of hDPSCs was reduced, despite an increase in osteogenic/odontogenic activity. Clinical relevance: Introduction of noninvasive methods in regenerative endodontic treatments.

Abnormal odontogenesis following management of childhood cancer (retinoblastoma): review and a new variant.

A young child being diagnosed with cancer naturally generates a pretty melancholy reaction. Each cancer can be managed with a vast array of treatment options that are available either individually or as a combination, the final goal of which is total eradication of the condition in the affected individual. Since, most of these treatments are administered during the age of tooth formation, they may affect stages of odontogenesis. Most common treatment of childhood cancers includes--chemotherapy and radiotherapy. With recent advancements in cancer therapy additional treatment options like laser therapy, radiation in the form of brachytherapy or teletherapy, cryotherapy, thermochemotherapy, etc. are available. As treatment of childhood cancers starts at a very young age coinciding with dental development, a number of dental malformations have been reported in childhood cancer survivors. The most common ocular cancer in children is retinoblastoma. This is the first such reported case and unique one where microdontia has affected all the first premolars.

Long-term effects of chemotherapy and radiation received during early childhood on the developing dentition of pediatric cancer patients.

INTRODUCTION: The short-term effects of chemotherapy and irradiation are well documented; however, there is paucity regarding their long-term effects, especially in children and adolescents. CASE DESCRIPTION: This paper discusses the long-term effects of chemotherapy and/or radiation received by the patients during their early childhood on the developing dentition. It comprises the compilation of 11 cases with alteration in the dental development screened from 138 cases of the childhood cancer patients who received the chemotherapy and/or radiation as a part of anticancer therapy. RESULTS AND CONCLUSION: The findings revealed that the age of initiation of anticancer therapy along with the synergistic effect of chemo-irradiation, and the dose of radiation used were the principal determinants for the dental abnormalities. The root-related abnormalities were found to be varied and more common as compared to the missing teeth and defects related to the tooth crown.

[Radiation-related caries: etiology and possible preventive strategies. What should the radiotherapist know?]. / Radiogene Karies: Ätiologie und Möglichkeiten der Prävention. Was sollte der Strahlentherapeut wissen?

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.

Disturbances in dental development and craniofacial growth in children treated with hematopoietic stem cell transplantation.

OBJECTIVES: To investigate the correlation between age, degree of disturbances in dental development, and vertical growth of the face in children treated with hematopoietic stem cell transplantation (HSCT). PATIENTS: 39 long-term survivors of HSCT performed in childhood and transplanted before the age of 12, at a mean age of 6.8±3.3 years. METHODS: Panoramic and cephalometric radiographs were taken at a mean age of 16.2 years. For each patient two age- and sex-matched healthy controls were included. The area of three mandibular teeth was measured and a cephalometric analysis was performed. RESULTS: The mean area of the mandibular central incisor, first and second molar was significantly smaller in the HSCT group, and the vertical growth of the face was significantly reduced, especially in the lower third, compared to healthy controls. A statistically significant correlation between age at HSCT, degree of disturbances in dental development, and vertical growth of the face was found. Children subjected to pre-HSCT chemotherapy protocols had significantly more growth reduction in vertical craniofacial variables compared to children without pre-HSCT chemotherapy. Conditioning regimens including busulfan or total body irradiation had similar deleterious effects on tooth area reduction and craniofacial parameters. CONCLUSIONS: The younger the child is at HSCT, the greater the impairment in dental and vertical facial development. This supports the suggestion that the reduction in lower facial height found in SCT children mainly is a result of impaired dental development and that young age is a risk factor for more severe disturbances.

Stimulatory effect of low-level laser therapy on root development of rat molars: a preliminary study.

Several studies suggest a biomodulatory influence of low-level laser irradiation in the inflammatory and reparative processes of dental tissues. The aim of this study was to investigate the stimulatory effect of 808-nm laser irradiation on root development of rat molars and also to evaluate the histological reaction of pulp and periapical tissues. Twenty-four 30-day-old Wistar male rats were randomly assigned to three-time and five-time laser therapy groups. After initial x-ray, using mammography equipment, laser energy was applied at a wavelength of 808 nm (2 J/cm(2), 100 mW, 20 s) to the midroot area of the lower molars of one side of mouth at repeated intervals of the 48 h. The animals were killed 1 day after the final treatment, and root length development of the experimental samples was compared to contra-lateral non-irradiated molars using mammography. The histological reaction of the pulp and periapical tissue was evaluated under light microscopy. Root development was more advanced in irradiated groups than in the non-irradiated controls (p < 0.001). No significant differences, however, could be found between the root development changes in the three-time and five-time laser therapy groups (p > 0.05). Histological findings showed that the occurrence of secondary cement formation was significantly higher in the irradiation groups compared to the controls (p = 0.003). However, there were no statistically significant differences for the frequencies of pulp hyperemia, periodontal ligament fiber organization, or lamina dura remodeling between the groups (p > 0.05). Under the conditions used in this study, 808-nm low-level laser accelerates the rat molar root development in the presence of favorable histological reactions.

Developmental dental defects linked with chemoradiotherapy: a case report.

Developmental orofacial dentoalveolar complications associated with chemoradiotherapy in an 8 year old child with a history of rhabdomyosarcoma are reported. This report details, clinically and radiographically, these effects in a child diagnosed at 3 years of age with a lesion primary to the left buccinator. Early evaluation is vital to determine potential dentoalveolar complications and long-term consequences.

DENTAL CARIES INTENSITY IN CHILDREN WITH DISTURBANCES IN TOOTH FORMATION, SURVIVED AFTER THE CHORNOBYL NPP ACCIDENT. / INTENSYVNIST' KARIIeSU U DITEI Z PORUShENNIaMY FORMUVANNIa ZUBIV, POSTRAZhDALYKh VNASLIDOK AVARIÏ NA ChORNOBYL'S'KII AES.

OBJECTIVE: assessment of dental caries intensity in children with disturbances in tooth formation living in radiologically contaminated territories as a result of the Chornobyl NPP accident. MATERIALS AND METHODS: Children aged 6-14 years old (n = 1470) suffering from disturbances in tooth formation(DTF) with the residents of radiologically contaminated territories (n = 528) among them were enrolled in the study.The DTF subtypes were assayed, namely the systemic enamel hypoplasia (SEH) and molar incisor hypomineralisation(MIH). Personal radiation history was recorded. Intensity of caries and caries of surfaces in the mixed (i.e. transitional) occlusion (df+DMF, dfs+DMFS coefficients) and permanent occlusion (DMF, DMFS coefficients) was identified. RESULTS: Caries intensity in the exposed children suffering DTF with mixed and permanent dental occlusion was sig-nificantly higher vs. either in children exposed to ionizing radiation with no DTF or in the control group (р < 0.001,р < 0.001 and р < 0.05, р < 0.001 correspondingly). The highest caries intensity of the permanent teeth was revealedin the residents of contaminated territories suffering SEH (6.95 ± 2.3) vs. cases of MIH (5.68 ± 1.97) as a result ofnonsymmetrical teeth involvement. CONCLUSIONS: The highest values of df+DMF, dfs+DMFS coefficients were diagnosed in children with a mixed dentalocclusion aged 6-14 years old living on territories contaminated as a result of the ChNPP accident as compared tothe not exposed subjects and control group (7.2 ± 2.07 and 8.98 ± 2.4, р < 0.001). A very high intensity of cariesand surface caries of permanent teeth (DMF = 6.79 ± 2.34, DMFS = 8.69 ± 2.75, р < 0.001) was established in children exposed to ionizing radiation and suffering DTF. Such a high intensity may be due to the impact of a set of negative factors including the ionizing radiation in low doses and peculiarities of economic component of social sta-tus of study subjects, namely the unbalanced diet. In case of permanent occlusion the intensity of caries and cariesof tooth of in children survived after the ChNPP accident and suffering SEH was significantly (р < 0.05) higher compared to the persons suffering MIH.

ODONTOLOGICAL EFFECTS OF IONIZING RADIATION (review). / ODONTOLOGIChNI EFEKTY IONIZUIuChOGO VYPROMINIuVANNIa (ogliad).

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. 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.

High-fluence low-power laser irradiation promotes odontogenesis and inflammation resolution in periodontitis by enhancing stem cell proliferation and differentiation.

Periodontitis can exert a severe impact on the life of patients, and the use of stem cell therapy for this disease is promising. The inflammatory response consequent to periodontitis can promote stem cell proliferation. Activated inflammation triggers inhibitory cytokine secretion, thus reducing inflammation subsequent to stem cell activation. High­fluence low­power laser irradiation (HF­LPLI) has the ability to regulate stem cell function through its effect on inflammation. Thus, the aim of the present study was to examine whether HF­LPLI is able to activate stem cells to promote regeneration in periodontitis by promoting inflammation resolution, as well as to evaluate the underlying mechanism of action if an effect is observed. Stem cells were treated with HF­LPLI following inflammation activation. Reverse transcription­quantitative polymerase chain reaction and EdU assay were used to evaluate cell proliferation and differentiation. Flow cytometry and immunofluorescence were also used to detect the ability of HF­LPLI to regulate the surrounding inflammatory environment. Animal models of periodontal disease were treated with stem cells and HF­LPLI, and regeneration was detected by hematoxylin and eosin staining and in vivo imaging. It was observed that HF­LPLI promoted inflammation resolution by reducing the excessive inflammatory response, and finally stimulated stem cell proliferation and differentiation. Furthermore, in vivo results revealed that stem cells treated with HF­LPLI induced bone regeneration. HF­LPLI stimulated stem cell proliferation and differentiation by promoting inflammation resolution subsequent to stem cell activation, providing a new strategy for the clinical treatment of periodontitis.

Micro-CT evaluation of the radioprotective effect of resveratrol on the mandibular incisors of irradiated rats.

The purpose of this study was to perform a microcomputed tomographic evaluation of the radioprotective effect of resveratrol on the volume of mandibular incisors of irradiated rats. A second aim was to make a quantitative assessment of the effect of x-ray exposure on these dental tissues. Twenty adult male rats were divided into four groups: control, irradiated control, resveratrol, and irradiated resveratrol. The resveratrol groups received 100 mg/kg of resveratrol, whereas the irradiated groups were exposed to 15 Gy of irradiation. The animals were sacrificed 30 days after the irradiation procedure, and their mandibles were removed and scanned in a microcomputed tomography unit. The images were loaded into Mimics software to allow segmentation of the mandibular incisor and assessment of its volume. The results were compared by One-way ANOVA and Tukey's post hoc test, considering a 5% significance level. The irradiated groups showed significantly diminished volumes of the evaluated teeth, as compared with the control group (p < 0.05). The resveratrol group presented higher values than those of the irradiated groups, and volumes similar to those of the control group. High radiation doses significantly affected tooth formation, resulting in alterations in the dental structure, and thus lower volumes. Moreover, resveratrol showed no effective radioprotective impact on dental tissues. Future studies are needed to evaluate different concentrations of this substance, in an endeavor to verify its potential as a radioprotector for these dental tissues.

Cervico-facial irradiation and orthodontic treatment.

Cancers during infancy and childhood affect 1 to 3% of children under the age of 15. Among these cancers the most frequent are malignant hemopathies, and in particular, acute lymphoblastic leukemia, which represents 80% of infant leukemias, with a peak of incidence around the age of 3-4. The overall prognosis for infant malignant hemopathies has improved significantly thanks to progress made in chemotherapy and radiotherapy. However, these anti-cancer treatments, particularly radiotherapy, when performed early, generally before 5 years of age, can have harmful effects that interfere with overall growth and particularly cranio-facial growth, and also with the child's oro-dental development. Some effects such as mandibular retrognathia, macrodontia, microdontia, agenesis and delayed eruption could increase the need for orthodontic treatment, while other complications, particularly the reduced height of the alveolar processes, short thin roots and modification of the superficial and profound periodontium, are likely to make such treatment more difficult. The aim of this review of the literature is to identify the essential factors that must be analyzed before orthodontic treatment is proposed for subjects who have undergone radiotherapy at an early age, and the precautions to be taken before and during orthodontic treatment.

Antibacterial and Odontogenesis Efficacy of Mineral Trioxide Aggregate Combined with CO2 Laser Treatment.

INTRODUCTION: Mineral trioxide aggregate (MTA) has been successfully used in clinical applications in endodontics. Studies show that the antibacterial effects of CO2 laser irradiation are highly efficient when bacteria are embedded in biofilm because of a photothermal mechanism. The aim of this study was to confirm the effects of CO2 laser irradiation on MTA with regard to both material characterization and cell viability. METHODS: MTA was irradiated with a dental CO2 laser using directly mounted fiber optics in the wound healing mode with a spot area of 0.25 cm(2) and then stored in an incubator at 100% relative humidity and 37°C for 1 day to set. The human dental pulp cells cultured on MTA were analyzed along with their proliferation and odontogenic differentiation behaviors. RESULTS: The results indicate that the setting time of MTA after irradiation by the CO2 laser was significantly reduced to 118 minutes rather than the usual 143 minutes. The maximum diametral tensile strength and x-ray diffraction patterns were similar to those obtained without CO2 laser irradiation. However, the CO2 laser irradiation increased the amount of Ca and Si ions released from the MTA and regulated cell behavior. CO2 laser-irradiated MTA promoted odontogenic differentiation of hDPCs, with the increased formation of mineralized nodules on the substrate's surface. It also up-regulated the protein expression of multiple markers of odontogenic and the expression of dentin sialophosphoprotein protein. CONCLUSIONS: The current study provides new and important data about the effects of CO2 laser irradiation on MTA with regard to the decreased setting time and increased ion release. Taking cell functions into account, the Si concentration released from MTA with laser irradiation may be lower than a critical value, and this information could lead to the development of new regenerative therapies for dentin and periodontal tissue.

Oral condition in children treated with bone marrow transplantation.

Oral health was studied in 49 children below 12 years of age treated with bone marrow transplantation (BMT). Dental treatment prior to BMT was required in 41% of the children. Ulceration of the mucous membranes in the mouth was observed in 37% of the patients during treatment. Those given methotrexate as prophylaxis against graft-versus-host disease (GVHD) exhibited oral ulcerations more frequently (p less than 0.05) than those given cyclosporin. One year after BMT all patients with a clinical chronic GVHD exhibited changes in the oral mucosa. During the first year after BMT 31% of the children developed carious lesions. Children treated with 10 Gy total body irradiation (TBI) had a significantly (p less than 0.05) reduced salivary secretion rate. Dental development was severely affected in children treated with TBI. These disturbances consisted of arrested root development, enamel hypoplasias and microdontia.

Long-term adverse effects on dentition in children with poor-risk neuroblastoma treated with high-dose chemotherapy and autologous stem cell transplantation with or without total body irradiation.

Chemo- and radiotherapy may have injurious effects on developing teeth. In this long-term follow-up study among poor-risk neuroblastoma (NBL) survivors our aims were: (1) to assess both the type and extent of the side-effects of the anticancer treatment on tooth development; and (2) to develop an index for expressing total damage to the permanent dentition. We studied the dental development from panoramic radiographs (PRG) of 18 long-term survivors treated under the age of 6 years with high-dose (HD) chemotherapy and autologous stem cell transplantation (ASCT) for poor-risk NBL. The myeloablative therapy was either HD chemotherapy and fractionated total body irradiation (TBI) of 10-12 Gy (TBI group, n = 10) or HD chemotherapy only (non-TBI group, n = 8). A defect index (DeI) was developed to describe the damage to the permanent dentition. The DeI was also tested in 18 healthy adolescents. All NBL patients had disturbances in dental development including short roots, arrested root development, microdontia and tooth aplasia. After TBI, 9/10 patients had very severe root defects, in contrast to none in the non-TBI group. All children in the TBI group had 2-12 (mean 6.6) missing permanent teeth, while 2/5 in the non-TBI group (3/8 excluded due to young age) had two and four missing permanent teeth, respectively. Microdontia was found at equal frequency in both groups. The mean value of the DeI was 70.0 (range 28-117) in the TBI group, 15.2 (range 4-34) in the non-TBI group (P<0.001, Mann-Whitney U test) and 1.8 (range 0-15) in healthy adolescents. Disturbances in dental development may compromise occlusal function in poor-risk NBL patients after ASCT, especially when TBI is included in the conditioning regimen. Long-term dental follow-up and rehabilitation is required.

Long-term effects of bone marrow transplantation on dental status in children with leukaemia.

Minimal data about oral and dental health in long-term survivors after BMT are available. We studied the dental status of 27 children (19 males, eight females) with leukaemia, followed up with a routine oral examination, panoramic tomogram and, when necessary, an endoral radiograph at a median of 2 years (range 1-10) after BMT. Community periodontal index treatment necessity (CPITN), dental caries, missing or filled permanent teeth (DMFT) and dento-facial alterations according to WHO criteria were registered and evaluated. Median age of the patients at BMT was 9 years (range 1.1-17.9). The mean DMFT score ranged from 1.6 to 12.4 according to age at examination and was slightly higher than that which we previously reported in children who received chemotherapy alone. CPITN showed the presence of soft deposits in 77.7%, serious gingivitis in 59.2% and parodontal involvement in 3.7% of cases. Dento-facial abnormalities were found in 55.5% of patients, while 62.9% of the patients had tooth abnormalities or agenesis. Nine out of 27 patients (33%) had root hypoplasia. A negative impact on DMFT index due to multiple post-BMT factors was found. Age is the crucial factor in determining a developmental defect of enamel and root. The follow-up of long-term survivors after BMT should include regular dental examination.

Hypodontia in the beagle after perinatal whole-body 60Co gamma irradiation.

As part of a long-term study to evaluate health effects of pre- and postnatal irradiation, dental development was examined. Beagles were irradiated in utero at 8, 28, or 55 days postcoitus or postnatally at 2, 70, or 365 days postpartum. Whole-body 60Co gamma radiation doses ranged from 0 to 3.8 Gy. There was an age-dependent dose-related increase in premolar hypodontia for animals irradiated at 55 days postcoitus or 2 days postpartum with doses of 0.83 Gy or higher and for those irradiated at 28 days postcoitus with 1.2 Gy or higher.

Histologic effect of fractionated doses of selectively applied 60Co irradiation on the teeth of albino rats.

This study compares the effects of fractionated 2400, 4800 and 7200 rad doses of Co-60 irradiation on the formed and developing teeth of the rats. The 7200 rad dosage was found to cause damage to both odontoblasts and ameloblasts of developing incisors but to spare previously formed molars.