Influence of photobiomodulation therapy on root development of rat molars with open apex and pulp necrosis.

This study aimed to evaluate the role of photobiomodulation (PBM) in apexification and apexogenesis of necrotic rat molars with an open apex. Rat molars were exposed to the oral environment for 3 weeks. Canals were rinsed with 2.5% NaOCl and 17% EDTA, filled with antibiotic paste and sealed. After 7 days, canals were rinsed and divided into six groups (n=6): mineral trioxide aggregate (MTA); blood clot (BC); human dental pulp stem cells (hDPSC); MTA+PBM; BC+PBM; and hDPSC+PBM. In hDPSC groups, a 1% agarose gel scaffold was used. Two groups were not exposed: healthy tooth+PBM (n = 6), healthy tooth (n = 3); and one was exposed throughout the experiment: necrotic tooth (n = 3). In PBM groups, irradiation was performed with aluminum gallium indium phosphide (InGaAlP) diode laser for 30 days within 24-h intervals. After that, the specimens were processed for histological and immunohistochemical analyses. Necrotic tooth showed greater neutrophil infiltrate (p < 0.05). Necrotic tooth, healthy tooth, and healthy tooth+PBM groups showed absence of a thin layer of fibrous condensation in the periapical area. All the other groups stimulated the formation of a thicker layer of fibers (p < 0.05). All groups formed more mineralized tissue than necrotic tooth (p < 0.05). PBM associated with MTA, BC, or hDPSC formed more mineralized tissue (p < 0.05). MTA+PBM induced apexification (p < 0.05). Rabbit polyclonal anti-bone sialoprotein (BSP) antibody confirmed the histological findings of mineralized tissue formation, and hDPSC groups exhibited higher percentage of BSP-positive cells. It can be concluded that PBM improved apexification and favored apexogenesis in necrotic rat molars with an open apex.

Influence of photobiomodulation therapy on root development of rat molars with open apex and pulp necrosis

Abstract This study aimed to evaluate the role of photobiomodulation (PBM) in apexification and apexogenesis of necrotic rat molars with an open apex. Rat molars were exposed to the oral environment for 3 weeks. Canals were rinsed with 2.5% NaOCl and 17% EDTA, filled with antibiotic paste and sealed. After 7 days, canals were rinsed and divided into six groups (n=6): mineral trioxide aggregate (MTA); blood clot (BC); human dental pulp stem cells (hDPSC); MTA+PBM; BC+PBM; and hDPSC+PBM. In hDPSC groups, a 1% agarose gel scaffold was used. Two groups were not exposed: healthy tooth+PBM (n = 6), healthy tooth (n = 3); and one was exposed throughout the experiment: necrotic tooth (n = 3). In PBM groups, irradiation was performed with aluminum gallium indium phosphide (InGaAlP) diode laser for 30 days within 24-h intervals. After that, the specimens were processed for histological and immunohistochemical analyses. Necrotic tooth showed greater neutrophil infiltrate (p < 0.05). Necrotic tooth, healthy tooth, and healthy tooth+PBM groups showed absence of a thin layer of fibrous condensation in the periapical area. All the other groups stimulated the formation of a thicker layer of fibers (p < 0.05). All groups formed more mineralized tissue than necrotic tooth (p < 0.05). PBM associated with MTA, BC, or hDPSC formed more mineralized tissue (p < 0.05). MTA+PBM induced apexification (p < 0.05). Rabbit polyclonal anti-bone sialoprotein (BSP) antibody confirmed the histological findings of mineralized tissue formation, and hDPSC groups exhibited higher percentage of BSP-positive cells. It can be concluded that PBM improved apexification and favored apexogenesis in necrotic rat molars with an open apex.

Generation and Role of Reactive Oxygen and Nitrogen Species Induced by Plasma, Lasers, Chemical Agents, and Other Systems in Dentistry.

The generation of reactive oxygen and nitrogen species (RONS) has been found to occur during inflammatory procedures, during cell ischemia, and in various crucial developmental processes such as cell differentiation and along cell signaling pathways. The most common sources of intracellular RONS are the mitochondrial electron transport system, NADH oxidase, and cytochrome P450. In this review, we analyzed the extracellular and intracellular sources of reactive species, their cell signaling pathways, the mechanisms of action, and their positive and negative effects in the dental field. In dentistry, ROS can be found-in lasers, photosensitizers, bleaching agents, cold plasma, and even resin cements, all of which contribute to the generation and prevalence of ROS. Nonthermal plasma has been used as a source of ROS for biomedical applications and has the potential for use with dental stem cells as well. There are different types of dental stem cells, but their therapeutic use remains largely untapped, with the focus currently on only periodontal ligament stem cells. More research is necessary in this area, including studies about ROS mechanisms with dental cells, along with the utilization of reactive species in redox medicine. Such studies will help to provide successful treatment modalities for various diseases.

Nutrition of the aged horse.

This article reviews current thoughts on nutrition of the older horse in health and disease. Common causes of weight loss and poor body condition in old horses include dental or oral cavity abnormalities, pituitary pars intermedia dysfunction, and reduced feed intake attributable to competition from herd mates or pain associated with osteoarthritis. Feed intake and body condition may improve after institution of management changes. Thin but otherwise healthy old horses can benefit from a diet that provides 12% to 16% crude protein and includes highly digestible feedstuffs. In horses with severe irreversible dental problems, long-stem fiber (hay) should be replaced by soaked hay cubes, short chopped hay, or heavily soaked sugar beet pulp. Evidence of chronic endocrine, hepatic, or renal disease dictates dietary modifications.

Osteological and dental markers of health in the transition from the Late Antique to the Early Medieval period in Croatia.

The purpose of this study is to analyze health at the transition from the Late Antique (LA) to the Early Medieval (EM) period in Croatia. Results of the analyses of skeletal remains are compared with historical and archaeological data to test the hypothesis that the transition was catastrophic. An additional objective is to determine whether the transition was a uniform process, or differentially affected the past inhabitants of Croatia because of various local considerations. To accomplish this, four markers of health: cribra orbitalia, linear enamel hypoplasia, nonspecific periostitis, and trauma were compared in 981 skeletons: 477 from nine urban LA sites, and 504 from six rural EM sites. Data were collected by sex and age for individual, and for co-occurrences of various features. Because continental and Adriatic Croatia has different ecological features, data were specifically tabulated for the two regions. Comparisons between the continental and Adriatic regions of the LA series showed no significant differences in the frequencies of the analyzed markers of stress. Comparisons between the LA and EM series showed similar frequencies in continental Croatia--suggesting no significant discontinuity of living conditions, and a significant increase of cribra orbitalia, periostitis, and trauma frequencies during the EM period in Adriatic Croatia. The deterioration of living conditions primarily affected subadults and males. These data suggest that the transition from the LA to the EM period in Croatia was not a uniform process, but differentially affected population biology most likely because of local cultural, socio-economical or political considerations.

[Average of the PCDFs value in blood in patients with Yusho in the 2001 to 2003 fiscal year and comparison between the clinical features and PCDFs].

BACKGROUND: Kanemi Yusho is the name given to a 1968 food poisoning incident resulting from the ingestion of PCB contaminated rice bran oil that had been used as a heating medium. At the time, victims presented with mainly cutaneous manifestations and various other symptoms such as of the eyes and teeth, general fatigue, headaches, and paresthesia of the extremities. The characteristic symptoms then resolved with time. Yusho patients have been followed from immediately after the incident. Blood levels of dioxins such as PeCDF have been measured for those who wishing to since 2001. SUBJECTS AND METHODS: The presence or absence of relationships between blood PeCDF level and various examination items/symptoms was investigated in 359 subjects whose blood levels of PCB-related chemical compounds such as PeCDF were measured in the Yusho related examinations between 2001 and 2003. Characteristic symptoms were also compared with the results of examinations done 15 years previously. RESULTS AND DISCUSSION: The average blood 2,3,4,7,8-PeCDF level in designated Yusho patients was 177.50 pg/g lipids; showing a markedly higher value than that of the normal control group (15.2 pg/g lipids). As well, the blood PeCDF level was related to PCB level, hexachlorobiphenyl level, urinary sugar, erythrocyte sedimetation rate (ESR) (2-hour), thymol and Na. There were also relationships with cutaneous findings (acneiform eruption and comedones), mucosal findings (oral pigmentation), constipation, numbness in the extremities, body weight loss, and abnormal abdominal ultrasonography. Symptoms seen in the skin and eyes in 2001 and 2003 had decreased compared with those in seen 1988. However, PCB and blood PeCDF levels remained high. Patients are continuing to present with mucosal and subjective symptoms as chronic conditions.

Skeletal evidence of health and disease in pre-contact Alaskan Eskimos and Aleuts.

There have been relatively few paleopathological studies of arctic populations to date, compared to other regions of North America. Studies aimed at elucidating patterns of health and disease in arctic peoples prior to contact and assessing inter- and intraregional differences in disease patterns have been particularly few. In the present study, five pre-contact skeletal samples (N = 193), representing 4 Eskimo populations from northern coastal Alaska and 1 Aleut population from the eastern Aleutian Islands, were examined macroscopically for the following indicators of health status: cribra orbitalia, porotic hyperostosis, trauma, infection, dental caries, abscesses, antemortem tooth loss, periodontal disease, and dental attrition. In addition, archeological and epidemiological data were used to help reconstruct the health of these populations. The goals of the analysis were 2-fold: 1) to assess the pre-contact health of North Alaskan Eskimos and Aleuts in order to provide a baseline comparison for the post-contact health of these groups, and 2) to determine if any differences in disease patterns exist between the Eskimos and Aleuts that might be related to differences in their physical environment, subsistence patterns, and cultural practices. The analysis revealed that both groups suffered from a variety of health problems prior to contact, including iron deficiency anemia, trauma, infection, and various forms of dental pathology. Statistical comparisons of the 2 groups revealed that Eskimos and Aleuts had different patterns of health and disease prior to contact. Most notably, the Aleuts had a significantly higher frequency of cranial trauma and infracranial infection than the Eskimos, while the latter had a significantly higher frequency of enamel hypoplasia. An examination of the physical and cultural environment of the 2 groups reveals several possible explanations for these differences, including warfare, subsistence pursuits, and housing practices. The documentation of these differences indicates that variability in pre-contact disease patterns can be identified between hunter-gatherer populations living in similar environments and exhibiting similar general lifestyles.

Ultrastructure of the ankylotic area in the osteopetrotic op/op mouse.

The op/op mouse, which carries an osteopetrotic mutation, suffers from complete failure of tooth eruption. Commonly the teeth are ankylosed to the bone. Previous reports of ankylosis in the op/op mouse have been based on light microscopy. The aim of this study was to clarify the ultrastructural features of the ankylotic area using the oolong tea extract (OTE) staining technique. The ultrastructural features of ankylosis did not parallel the findings of light microscopy. OTE staining clearly stained the collagen fibers of bone and tooth, and the space dividing the tooth and bone was revealed by transmission electron microscopy. In comparison, light microscopy failed to reveal this space and the ankylosis was unclear. The true ankylotic area was smooth and the tooth was tightly ankylosed to the bone.

The effects of hypocalcemia/hypophosphatemia on porcine bone and dental hard tissues in an inherited form of type 1 pseudo-vitamin D deficiency rickets.

The effects of Vitamin D deficiency rickets on the formation of mineralized dental tissues were studied in a breed of pigs which had moderate and marked hypocalcemia because of an inherited defect in the renal production of the biologically-active Vitamin D metabolites. Affected piglets developed classical symptoms of rickets which were fatal unless Vitamin D supplements were given. The dissected mandibles of homozygous (rickets) and heterozygous (normal) pigs were photographed and radiographed. Compared with those of normal pigs, the mandibles of homozygous pigs demonstrated slowed development/eruption of permanent teeth, under-mineralized bone, underdeveloped dentin (enlarged pulp chambers), interglobular dentin, and enamel hypoplasia. Enamel defects in rachitic pig teeth were difficult to observe radiographically, but could be detected visually and by SDS-PAGE analysis of the enamel protein components of developing and maturing enamel. There was significant retention of amelogenins in the enamel maturation zones of developing molars taken from rachitic pigs, but there was no obvious difference in the patterns of amelogenin processing.

[Dentofacial manifestations in children with vitamin D-dependent Rickets type II].

Calcification of the teeth, size of the teeth and dental arches, facial growth and calcification of the carpal bones were studied in three children with clinically different severities of vitamin D-dependent rickets (DDR), type II, with alopecia, which is 1,25-dihydroxyvitamin D-receptor-defect rickets and is particularly resistant to treatment with calciferol analogues. They were treated in a pediatric clinic with large doses of 1 alpha-hydroxyvitamin D3(1 alpha-(OH)D3) and 2 g/day of calcium lactate. The results were as follows: 1. Hypoplasia of enamel of the deciduous teeth was not found. 2. In the deciduous teeth, large pulp chambers and thin dentin were seen in radiographs before treatment. In patients 1 and 2, these abnormalities were reversed by treatment. In patient 3, who had the severest manifestations, large pulp chambers and thin dentin decreased but still remained. 3. Growth of permanent teeth was retarded before treatment and during resistance to treatment. After effective medication, it caught up and was corrected. 4. Problems concerning maxillary and mandibular growth were not found. However Nasions of three patients were more front and lower and Orbitals were lower than standard. 5. In patients 1 and 2, the calcification of carpal bones was accelerated and in patient 3 retarded. 6. Mesiodistal dimensions of erupted deciduous and permanent teeth were within the standard range, except for patient 3, who had smaller lower deciduous teeth. 7. A ground section of the extracted upper right first deciduous molar from patient 3 showed abundant inter-globular dentin and lack of pre-dentinal layer. From the above findings, it was felt that in all probability dentinogenesis was disturbed by the DDR type II. Abnormally large pulp chambers and thin dentin could be corrected by effective medication. In patients with vitamin D-dependent rickets type II, oral hygiene for caries prevention is the most important procedure, because the pulp will be infected immediately after initiation of dental caries. After effective medication, permanent teeth and jaw bones will probably grow normally.

Vitamin D-dependent rickets type II: report of three cases.

In this study the dental findings of three patients with vitamin D-dependent rickets (DDR) type II with alopecia, who were treated with large doses of vitamin D3 derivatives, are described. Dental development that is at or near a normal level can be achieved in controlled patients, permitting routine treatment of carious teeth.

Structural and microanalytical changes in dentition after radiotherapy applied in cases of tumour in the oral cavity region.

Morphological observations by means of the scanning electron and optical microscopes as well as microanalytical qualitative and quantitative tests concerning content and distribution of calcium, phosphorus and magnesium in the teeth being in irradiation field were made in patients treated for larynx cancer by methods of radiotherapy. The teeth enamel was in some places thinner and in some others it was lacking. The characteristic defects took place in the form of notches, cracks and of superficial destruction. In X-ray microanalyser the enamel showed some features of demineralization. In dentine, features of demineralization and on the other hand features of remineralization were seen. The root dentin, in which destructive processes but also reparation processes developed by root cement could be seen, was rather characteristic. Clear structural changes and disturbances of mineralization in hard tooth tissues being under therapeutic X-ray irradiation were observed.

Observations of dental diseases among prehistoric populations of Hungary.

The incidence of dental disease among people in developing countries today raises questions about the variation in the oral health of prehistoric populations. Considering these questions, we offer observations describing several types of dental disease which occurred among certain prehistoric populations of Hungary. The dental remains of 162 individuals recovered from seven sites of the Neolithic, Copper, and Bronze Age periods were examined for evidence of caries, hypoplasia, and periodontal disease. Appropriate methods were used to describe and record these dental lesions. The incidence of dental caries was low by comparison to other prehistoric agriculturists except for two forms of root caries: cervical and cemental. These types accounted for 68% of all the carious teeth recorded. Enamel hypoplasia was also lower than expected, occurring on only 4% of the total number of teeth. Periodontal abscesses were rare but other milder forms of periodontal lesions were frequent. Alveolar bone resorption occurred in varying degrees and followed the expected age distribution. The few exceptions were children or adolescents whose crania had other lesions suggesting a mineral metabolic disturbance. The lower incidence of enamel caries is likely due to high fluoride ingestion which also may have influenced the expression of enamel hypoplasia. No clear population trends were seen in dental disease incidence except for cemental caries which were found among Copper and Bronze Age remains.