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PubMed2004

[Preservation of alveolar bone of un-restorable traumatized maxillary incisors for future].

UNLABELLED: Anterior maxillary implantation is a challenging treatment for both the surgeon and prosthodontist due to high esthetic demands in this area. However, it is the most traumatized and most exposed region to habits. Prompt and appropriate management can significantly improve prognosis of many dentoalveolar injuries, especially in young patients. Unfortunately, many traumatized teeth are overtreated or left untreated, which lead to a much more complicated treatment at the time of permanent restoration at adulthood. The facial cortical plate over the roots of the maxillary teeth is thin and porous. Periapical infections, as well as prolonged and stubborn surgical treatments (repeated root end surgeries) can cause resorption of the labial plate, migrate to a more palatal position, and may later require an augmentation procedure prior to implant placement. The treatment-options of traumatized, anterior maxillary, un-restorable fractured root and ankylosed infraocluded teeth, in relation to preservation of the adjacent alveolar bone for future use of dental implantation will be discussed. The recommended treatment of crown-root fracture of permanent incisor includes removal of the coronal fragment and supragingival restoration of the fractured root. In severe cases in which the fracture line positions deeply under the gingival margin, this treatment may be supplemented by gingivectomy and/or osteotomy, as well as surgical or orthodontic extrusion of the root. In young patients, use of these treatment options as temporary treatment to preserve the facial cortical plate is important. Preservation of alveolar dimension will enable implantation after the completion of growth and development. Dento-alveolar ankylosis accompanied by replacement resorption is a serious complication following severe injury to the periodontal membrane. This complication develops mainly following avulsion and intrusion but also following lateral luxation and root fracture. Replacement resorption develops after severe damage to the periodontal ligament cells that cover the root surface. As a result of this damage, the periodontal ligament is replaced by bone tissue, causing ankylosis between bone and tooth. Following ankylosis, resorption of cementum and root dentin occurs. These processes eventually result in replacement of the entire root by bone. In young children it could arrest the growth of the alveolar process and create an infra-occluded tooth, resulting in a severe bony defect that is difficult to correct. In addition, loss of the maxillary incisor leads to serious esthetic and restorative problems, particularly when the trauma occurs at a young age. Therefore, ankylosed teeth should be treated as soon as diagnosed. Alternative treatments include intentional extraction and immediate replantation of the ankylosed tooth to its socket after embedding the tooth and the socket in Emdogain. This treatment is indicated only when the ankylosis or the replacement resorption is diagnosed at an early stage or has affected only a small area of the root. When the resorption is diagnosed at a later stage, auto transplantation of first lower pre-molar to the anterior region or decoronation of the ankylosed tooth may be considered. Decoronation is a simple and safe surgical procedure for preservation of alveolar bone prior to implant placement. It should be considered as a treatment option for teeth affected by replacement resorption. The alternative treatment of surgical extraction of an ankylosed tooth often leads to considerable bone loss and reduced bone volume in the oro-facial dimension. This may later necessitate an augmentation procedure. CONCLUSION: Scrupulous diagnosis of teeth and the alveolar bone after a traumatic injury is necessary. Treatment is multidisciplinary, requiring endodontic, surgical, orthodontic, operative and prosthetic compliance. An individual treatment plan for each patient is necessary. General rule do not apply. Periodic check-up is essential.

Adult↗
PubMed1995

The origin of fibroblasts and their role in the early stages of horizontal furcation defect healing in the beagle dog.

The origin of fibroblasts, their proliferative activity and roles in the early stages of periodontal repair were investigated in order to better understand the periodontal healing process in furcation defects of the beagle dog after guided tissue regenerative therapy. Newly divided cells were identified by immunolocalization of bromodeoxyuridine (BrdU) injected 1 hour prior to sacrificing the animals. At 1 and 2 weeks after creation of the defects, the lesions were occupied primarily by granulation tissue. Under this condition, periodontal ligaments (PDL) fibroblasts in a coronal portion of the remaining PDL close to wounds proliferated actively, migrated along the root surface and formed fibrous connective tissue on the surface. Similarly, the fibroblasts adjacent to the bone surface also showed proliferative activity and engaged in active formation of fibrous connective tissue on the bone surface. The majority of labeled cells in both areas were located in the extravascular area. At 3 and 4 weeks, the defects were filled with an increased amount of new connective tissue and bone. The labeled fibroblasts were preferentially found in the most coronal portion of connective tissue formed on the root surface that was in direct contact with inflamed tissue, and the collagen fibers projected into granulation tissue. In areas of active bone formation, numerous labeled fibroblasts were located in connective tissue adjacent to the newly-formed bone. However, fibroblasts in the endosteum of new bone were rarely labeled These results indicate that fibroblasts involved in periodontal repair originate primarily from both the remaining PDL and alveolar bone, and actively engage in fibrous connective tissue formation in the early stages of periodontal repair The ability of PDL fibroblasts to proliferate, migrate, and form connective tissue on the root surfaces in the early repair stages appears to play a crucial role in the formation of the PDL and cementum, and consequently, in periodontal regeneration in the absence of root resorption and ankylosis. As the formation of new connective tissue and bone continues, the precursor cells for fibroblasts and osteoblasts are supplied locally through the continued divisions of the fibroblastic cells in association with the newly-formed connective tissue. Paravascular and endosteal cells appear to be minor contributors to new cell population during furcation defect repair in the beagle dog.

Alveolar Process↗
PubMed1997

Evaluation of orthodontic treatment with early extraction of four second molars.

The outcome of orthodontic treatment involving early extraction of 4 second molars was evaluated in 52 patients (29 girls, 23 boys). Computer-assisted analysis of cephalograms, casts and panoramic X-rays was performed at the start (T1, mean age 11.5 years) and at the end (T2, mean age 14.4 years) of treatment. Following treatment, mesial migration of upper and lower first molars was counteracted; however, treatment only moderately influenced normal development of the position of the incisors and the profile. At the end of treatment, the third molars had erupted in only 3 patients. Nevertheless, on average a significant mesial movement of these teeth was observed. In addition, there was a significant improvement in the axial inclination of the third molars, especially in the upper arch. This improvement was correlated with the original position of the teeth. All patients needed a longer follow-up period and it seems reasonable that some of them might require a second treatment phase to adjust the position of the third molars.

Adolescent↗
PubMed2005

Craniofacial and dentofacial development in pigs fed soft and hard diets.

INTRODUCTION: Several authors have found a correlation between reduced chewing activity and malocclusion. In animal experiments, it has been possible to correlate a diet of low chewing resistance to narrower arches, which predispose the subject to crowding and irregular teeth. METHODS: In this study, 17 pigs were weaned at 5 weeks of age and divided into 2 groups according to diet and housing. The soft-diet, indoor group was housed in conventional pens, and the animals were fed aliquots of barley and oats with soya and a mineral-vitamin premix added. The food was mixed with water at a dry matter content of about 25%. The hard-diet, outdoor group was kept outdoors; the pigs were fed solid food and also ate organic matter in the soil. All pigs were killed at 22 months of age. The skulls were dissected, and transverse and sagittal craniofacial and dentofacial dimensions were measured. RESULTS: Chewing hard food caused considerable occlusal and approximal attrition in the experimental animals. The dental arches were shorter due to this attrition and to mesial migration of the molars and premolars. The approximal attrition also reduced the tendency for crowding and rotation of the teeth. Posterior crossbite was more common among the hard-chewing animals. CONCLUSIONS: The increase in arch width in the hard-diet animals reported in the literature was not duplicated in this study. On the contrary, the soft-diet pigs had significantly wider arches than the hard-diet animals. This was most pronounced in the premolar region and could be the result of an atypical tongue habit, caused by the nonphysiologic feeding of the pigs. The soft-diet pigs also had a greater tendency to postnormal occlusion, especially in the canine region.

Animals↗
PubMed2006

Intrinsic causes of erosion.

Gastric juice entering the mouth causes dental erosion. Common causes for the migration of gastric juice through the lower and upper oesophageal sphincters are reflux disease, eating disorders, chronic alcoholism and pregnancy. Gastro-oesophageal reflux is a common condition affecting up to 65% of the western population at some point in their lifetime. A typical clinical sign of acidic gastric juice entering the mouth is palatal dental erosion. As the condition becomes more chronic it becomes more widespread. There have been relatively few randomised studies investigating the aetiology of acids causing erosion. Of the few that have reported their findings, it appears that gastric acids are equally likely to induce moderate-to- severe erosion as in dietary acids. This literature review reports the conditions associated with the movement of gastric juice and dental erosion using medical and dental sources.

Alcoholism↗
PubMed1989

Cell and fiber responses to cementum from periodontitis-affected root surfaces after citric acid treatment.

The purpose of this study was to assess connective tissue and epithelial responses to periodontitis-affected cementum (from exposed roots of human teeth) after surface demineralization with citric acid. Cementum specimens were obtained from root surfaces covered by calculus. Each rectangular specimen had a face of cementum and an opposite surface composed of pulpal dentin. One half of the specimens were treated with citric acid (experimental group), while the remainder served as untreated control specimens. Specimens were implanted vertically into incisional wounds on the dorsal surface of rats with one end of the implant protruding through the skin. 4 specimens in each group were available for examination 1, 3, 5, and 10 days after implantation. Histologic and histometric analyses of the implants included counts of adhering cells, evaluation of attached connective tissue fiber density and diameter, and assessment of epithelial migration. At 1 day, a distinct zone of surface demineralization was not present on the surface of the cementum in the experimental group, although such a zone was present on the dentin surfaces of the same specimens. Histometric comparisons between experimental and control groups at 1 day showed no differences in cell attachment or length of cementum surface within connective tissue. By 10 days, there was a trend for greater cell attachment to demineralized cementum, but the differences were not statistically significant. Although connective tissue fiber attachment has been shown to occur to demineralized dentin and to normal cementum in this model system, fiber attachment did not occur to the cementum in the present study.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Placement of a porous membrane underneath the mucoperiosteal flap and its effect on periodontal wound healing in dogs.

This study was designed to investigate the healing of surgically induced, horizontal periodontal defects in dogs following placement of a biocompatible, porous polytetrafluorethylene membrane around the roots of the treated teeth and to compare the healing to that of control teeth without membrane. Mandibular premolar teeth of 5 beagle dogs were used for experimentation. Specimen blocks were removed 3 months postoperatively for histological evaluation of contralateral experimental and control teeth. Mean apical migration of junctional epithelium among the experimental surfaces amounted to 0.1 mm as compared to 1.3 mm for the control surfaces. Accordingly, the amount of connective tissue attachment, defined by the distance from the base of the junctional epithelium to the apical termination of root planing, was greater for experimental than for control surfaces. As this increased amount of connective tissue attachment was associated with more coronal bone apposition, a periodontal ligament space was more prevalent in experimental than in control surfaces. A limited amount of ankylosis was observed for both experimental and control surfaces. Root resorption was more prevalent in control than in experimental surfaces. Conceivable reasons for the differences in healing between experimental and control teeth are discussed.

Alveolar Process↗
PubMed1984

Biosynthesis of salivary proteins in the parotid gland of the subhuman primate, Macaca fascicularis. Cell-free translation of the mRNA for a proline-rich glycoprotein and partial amino acid sequence and processing of its signal peptide.

The major anionic proline-rich proteins in the parotid and submandibular secretions of subhuman primates and man perform the important biological function of inhibiting crystal growth of calcium phosphate salts from saliva, which is supersaturated with calcium phosphate salts, thereby preventing excess deposition of hydroxylapatite on tooth surfaces. The present work was initiated as a first step towards investigating proline-rich protein biosynthesis in parotid glands using the subhuman primate, Macaca fascicularis, as a model system. RNA was isolated from macaque parotid glands and separated into poly(A)-enriched and poly(A)-deficient fractions by chromatography on oligo(dT)-cellulose. The mRNAs in both fractions promoted incorporation of radiolabeled amino acids into polypeptides in an mRNA-dependent reticulocyte lysate translation system. Five major proline-rich polypeptides were detected and one of these was shown to be the in vitro precursor of the major anionic macaque proline-rich protein (MPRP), which is the structural and functional counterpart of the major anionic proline-rich proteins in the parotid and submandibular secretions of man (Oppenheim, F.G., Offner, G.D., and Troxler, R.F. (1982) J. Biol. Chem. 257, 9271-9282). Radiosequencing of the material in anti-MPRP immune precipitates showed that the in vitro precursor of MPRP contained an 18-residue signal peptide. The in vitro precursor of MPRP was processed in dog pancreas vesicles to a form with a lower apparent Mr and with an NH2-terminal amino acid sequence identical to that of native MPRP. The phenylthiohydantoin derivatives of Ala and Ile were detected at residue 9 and those of Val and Met were detected at residue 16 of the signal peptide. This indicated that the in vitro precursor of MPRP, which migrated electrophoretically as a single band in anti-MPRP immune precipitates, contained two different in vitro polypeptides derived from two different mRNAs. These results are discussed in the context of the genetic polymorphism among the major anionic proline-rich proteins in the parotid and submandibular secretions of man.

Animals↗
PubMed1989

[In vitro cultivation of human pulpal fibroblast strains--permanent and deciduous teeth].

We succeeded in separating and the cultivating stable monolayer cultures of dental pulp fibroblast strains derived from permanent and deciduous human teeth. Human permanent (n = 67) and deciduous teeth (n = 26) were extracted under acupuncture anaesthesia for the correction of malocclusion. After splitting the teeth, the pulp tissues were carefully removed, placed in tissue culture flasks, and grown in Dulbecco's modified Eagle medium supplemented with 10% fetal calf serum (FCS). The human pulpal fibroblasts (HPF) of permanent teeth and deciduous teeth (DHPF) were subcultured. Both the HPF and DHPF appeared to migrate from adherent tissues within 24 to 48 hr after explanation. They proliferated in the pulp explants, and lined up in parallel rows of cells closest to the explant tissue within 7 to 10 days in all of the experimental cases. The outgrowing cells were subcultured at 1.3 x 10(4) cells/cm2 in tissue culture flasks every 4-11 days. They showed vigorous proliferation. The average number of cells in the 6-7 day cultures of HPF were 5.6 x 10(4) cells/cm2 from 3 to 16 passages. It was 4.7 x 10(4) cells/cm2 from 3 to 10 passages with DHPF. However, no difference was observed between HPF and DHPF in the amount of synthesized protein in culture flasks. Furthermore, the growth rate of DHPF was more sensitive than that of HPF to the FCS percentages of the culture media.

Cell Division↗
PubMed2001

Reactive pocket epithelium in untreated chronic periodontal disease: possible derivation from developmental remnants of the enamel organ and root sheath.

The pathological lining epithelium of destructive periodontitis was studied by analysis of the expression of intermediate filament proteins in biopsies of untreated advanced periodontitis. The cytokeratin (CK) pair 8/18 characteristic of simple epithelia was expressed consistently in a distribution pattern confined to the reactive pocket epithelium. The pattern of CK8/18 expression was complex with two broad presentations evident. In two-thirds of the advanced disease biopsies, the entire pathological lining epithelium was strongly reactive for both CK8 and CK18. In the remainder, the more superficial lining epithelium was mixed with foci of reactive and unreactive cells, with the deeper epithelium uniformly reactive. Only occasional highly localised reactivity for the simple keratins (CK8/18) was found in the lining epithelia of biopsies from minimally inflamed periodontal tissues. The pathological lining epithelium of advanced periodontitis was further characterised by the co-expression in basal layers of CK14, and of CK13 but not CK4, which are characteristic of suprabasal layers of stratified squamous epithelia. Cytokeratin 17, a marker of high turnover and migrating epithelial cells was extremely variable with no clear association between expression pattern and location of the epithelium ordisease status. There was no reactivity for CK10/11 typical of cornifying cells nor of vimentin, the characteristic intermediate filament of mesenchymal cells. The intermediate filament protein profile of the reactive lining epithelium was indistinguishable from the reactive epithelium present in three of five biopsies of periapical granulomas containing hyperplastic epithelium from activation of the developmental remnants of Hertwig's sheath, known as the cell rests of Malassez. The data reported are compatible with a contribution by remnants of developmental epithelium, including the reduced enamel epithelium and the cell rests of Malassez, to the reactive lining epithelium of the subgingival pocket in the pathogenesis of chronic periodontitis.

Adult↗
PubMed1993

Periodontal cell migration into the apical pulp during the repair process after pulpectomy in immature teeth: an autoradiographic study.

The migration of dental papilla cells into the periodontium during the process of root development may occur as part of the process involved in the formation of the periodontal tissues. The question posed is whether such cells under pathological conditions could retromigrate from periodontium into dental pulp and together with other apical pulp cells of immature teeth, take part in the production of additional dental tissue, e.g. 1) the tertiary/dentine under deep carious lesion where odontoblasts had been destroyed 2) the dentine bridge on an amputation wound and 3) calcified tissue which closes an apex during the apexification process in immature teeth. The migration of periodontal cells locally marked by H3 thymidine immediately after partial pulpectomy in immature dog's teeth was analysed at observation periods of 2, 24 and 50 h and also without H3 thymidine labelling of periodontal cells 8 weeks after pulpectomy. The marked cells were found in the early observation periods after pulpectomy just in the places where the hard tissues were formed in the later observation period of 8 weeks. They were found in large numbers just around the coagulated necrotic foci. The finding supports the assumption that firm necrotic masses are a very important stimulative factor in the reparation process in pulp and periodontium. The experiment also corroborated the existence of periodontal cell retromigration into apical dental papilla of immature teeth. Future research should assess the possible role of the pathological condition in the determination of undifferentiated odontogenic ectomesenchymal periodontal cells into odontoblasts.

Animals↗
PubMed2007

Analyses of a novel L130F missense mutation in FOXC1.

OBJECTIVE: To understand how the novel L130F mutation, found in 2 patients with Axenfeld-Rieger syndrome, disrupts function of the forkhead box C1 protein (FOXC1). METHODS: Sequencing DNA from patients with Axenfeld-Rieger syndrome identified a novel missense mutation that results in an L130F substitution in the FOXC1 gene. Site-directed mutagenesis was used to introduce the L130F mutation into the FOXC1 complementary DNA. The level of L130F protein expression was determined by means of immunoblotting. We determined the mutant protein's ability to localize to the nucleus, bind DNA, and transactivate a reporter construct. RESULTS: The FOXC1 L130F mutant protein is expressed at levels similar to those of wild-type FOXC1. The L130F protein, however, migrated at an apparent reduced molecular weight compared with the wild-type protein, suggesting that the mutant and wild-type proteins may be differentially phosphorylated. The L130F protein also had a significantly impaired capacity to localize to the nucleus, bind DNA, and transactivate reporter genes. CONCLUSIONS: The disease-causing L130F mutation further demonstrates that helix 3 of the forkhead domain is important for the FOXC1 protein to properly localize to the nucleus, bind DNA, and activate gene expression. CLINICAL RELEVANCE: The inability of FOXC1 to function owing to the L130F mutation provides further insight into how disruptions in the FOXC1 gene lead to human Axenfeld-Rieger syndrome.

Abnormalities, Multiple↗
PubMed2006

Sequence of mammalian fossils, including hominoid teeth, from the Bubing Basin caves, South China.

A Plio-Pleistocene to Holocene faunal sequence has been recovered from four carefully excavated caves in the Bubing Basin, adjacent to the larger Bose Basin of South China. The caves vary in elevation; we suggest that the higher caves were formed and filled with sediments prior to the lower caves. The highest deposits, which are from Mohui Cave, contain hominoid teeth and other fossilized remains of mammalian taxa most similar to late Pliocene and early Pleistocene faunas. Wuyun Cave ( approximately 50m lower in elevation than Mohui) contains a late middle Pleistocene fauna, which is supported by U-series age constraints from 350 to 200ka. Lower Pubu Cave ( approximately 23m below Wuyun) is assigned to the late Pleistocene, while the Cunkong Cave (the lowest, approximately 2m lower elevation than Lower Pubu) preserves a Holocene fauna. The four faunal assemblages indicate species-level changes in Ailuropoda, Stegodon, and Sus, the appearance of Elephas, the local disappearance of Stegodon, and the migration of Equus hemionus to South China. These initial results of our work call into question the continued value of the Stegodon/Ailuropoda Fauna, a category long used to characterize the Pleistocene faunas of South China. Excavation of karstic caves of varying elevation within the basins of South China holds promise for defining local sequences of mammalian fossils that can be used to investigate faunal variations related to climate change, biogeographic events, and evolutionary change over the past two million years. Stable isotopic analysis of a small sample of mammalian teeth from Bubing Basin caves is consistent with 100% C(3) vegetation in the Bubing/Bose region, with certain delta(13)C values consistent with a canopied woodland or forest. A preliminary assessment of the hominoid teeth indicates the presence of diverse molar and premolar morphologies including dental remains of Gigantopithecus blacki and a sample with similarities to the teeth reported from Longgupo.

Animals↗
PubMed1997

In vitro studies on periodontal ligament cells and enamel matrix derivative.

The recognition that periodontal regeneration can be achieved has resulted in increased efforts focused on understanding the mechanisms and factors required for restoring periodontal tissues so that clinical outcomes of such therapies are more predictable than those currently being used. In vitro models provide an excellent procedure for providing clues as to the mechanisms that may be required for regeneration of tissues. The investigations here were targeted at determining the ability of enamel matrix derivative (EMD) to influence specific properties of periodontal ligament cells in vitro. Properties of cells examined included migration, attachment, proliferation, biosynthetic activity and mineral nodule formation. Immunoassays were done to determine whether or not EMD retained known polypeptide factors. Results demonstrated that EMD under in vitro conditions formed protein aggregates, thereby providing a unique environment for cell-matrix interaction. Under these conditions, EMD: (a) enhanced proliferation of PDL cells, but not of epithelial cells; (b) increased total protein production by PDL cells; (c) promoted mineral nodule formation of PDL cells, as assayed by von Kossa staining; (d) had no significant effect on migration or attachment and spreading of cells within the limits of the assay systems used here. Next, EMD was screened for possible presence of specific molecules including: GM-CSF, calbindin D, EGF, fibronectin, bFGF, gamma-interferon, IL-1 beta, 2, 3, 6; IGF-1,2; NGF, PDGF, TNF, TGF beta. With immunoassays used, none of these molecules were identified in EMD. These in vitro studies support the concept that EMD can act as a positive matrix for cells at a regenerative site.

Calbindins↗
PubMed2006

Using recombinant platelet-derived growth factor to facilitate wound healing.

Recombinant human platelet-derived growth factor (rhPDGF-BB) is a bioactive protein that has been combined with bone graft materials in an effort to regenerate the periodontium to its prediseased state more predictably. The combination of a biocompatible scaffold with this highly purified, recombinant human growth factor capitalizes on PDGF's stimulatory effects on cellular migration and proliferation, with subsequent matrix formation, to drive the healing process toward regeneration. When using a growth factor such as rhPDGF-BB with broad wound healing activity, an added clinical benefit is the more rapid soft tissue wound healing pattern observed at the surgical site. This also may be seen as a patient-centered benefit because it allows dentists to provide for a patient's prosthetic care on a timely basis, leading to a faster return to normal function. Also, the patient may resume plaque control efforts earlier, which further facilitates the wound-healing process. The purpose of these 2 case reports is to document the use of rhPDGF-BB as a wound-healing agent in 2 clinical situations and to provide a rationale for its use in this capacity.

Aged↗
PubMed2005

Application of denaturing gradient gel electrophoresis (DGGE) to the analysis of endodontic infections.

The recent expanding use of cultivation-independent techniques for bacterial identification is reliant on the lack of knowledge of the conditions under which most bacteria are growing in their natural habitat and the difficulty to develop culture media that accurately reproduce these conditions. A molecular method that has been recently used in several areas to examine the bacterial diversity living in diverse environments is the denaturing gradient gel electrophoresis (DGGE). In DGGE, polymerase chain reaction (PCR)-generated DNA fragments of the same length but with different base-pair sequences can be separated. Separation is based on electrophorectic mobility of a partially melted double-strand DNA molecule in polyacrylamide gels, which is decreased when compared with that of the completely helical form of the molecule. Molecules with different sequences may have a different melting behavior and will therefore stop migrating at different positions in the gel. Application of the PCR-DGGE method in endodontic research has revealed that there are significant differences in the predominant bacterial composition between asymptomatic and symptomatic cases. This suggests that the structure of the bacterial community can play a role in the development of symptoms. In addition, new bacterial phylotypes have been disclosed in primary endodontic infections. PCR-DGGE has also confirmed that intra-radicular infections are a common finding in root-filled teeth associated with persistent periradicular lesions. The microbiota in failed cases significantly vary from teeth to teeth, with a mean number of species far higher than previously shown by culturing approaches. Application of the PCR-DGGE technique in endodontic microbiology research has the potential to shed light on several aspects of the different types of endodontic infection as well as on the effects of treatment procedures with regard to infection control.

Bacteria↗
PubMed2006

Stable carbon and nitrogen isotope ratio profiling of sperm whale teeth reveals ontogenetic movements and trophic ecology.

Teeth from male sperm whales (Physeter macrocephalus) stranded in the North-eastern Atlantic were used to determine whether chronological profiles of stable isotope ratios of C (delta(13)C) and N (delta(15)N) across dentine growth layers could be used to detect known ontogenetic benchmarks in movements and trophic ecology. Profiles showed a general decrease in delta(13)C (median = 1.91 per thousand) and an increase in delta(15)N (median = 2.42 per thousand) with age. A marked decline in delta(13)C occurred for all 11 teeth around 9-10 years and again for six individuals around 20 years. After the early twenties the delta(13)C continued to decline with age for all teeth. These results are consistent with males segregating from natal groups in low latitudes with the onset of puberty between 4 and 15 years and gradually dispersing pole-ward into (13)C-depleted temperate waters. Penetration into further depleted, productive high latitudes after the age of 20 might facilitate the spurt of accelerated growth rate observed around this age. Breeding migrations back to lower latitudes were not reflected in the delta(13)C profiles possibly due to being short compared to the time spent feeding in high latitudes. The timings of marked isotopic change in the delta(15)N profiles reflect those of the delta(13)C profiles, suggesting a link between dietary changes and movements. The observed increase in delta(15)N with age is likely to be caused by a trophic level increase as males grow in size, probably feeding on larger prey. An additional explanation could be that, in the higher latitudes of the North Atlantic, the main prey source is the high trophic level squid Gonatus fabricii. Also, the lower latitudes from where males disperse are depleted in basal (15)N. Profiles of delta(13)C and delta(15)N in sperm whale teeth gathered from different regions, sexes, and periods in time, could provide a unique way to understand the ecology of this species across different oceans.

Age Factors↗
PubMed2003

Dental caries in postwar Bosnia and Herzegovina.

OBJECTIVES: To present the prevalence of dental caries in postwar Bosnia and Herzegovina (BH). METHODS: A survey focused on dmft and DMFT indices was carried out in four cantons of the Federation of BH in 1997. The dental health of 6- and 12-year-olds was assessed in random samples (n = 238 and 318, respectively). DMFT index in adult population was assessed in clients coming to dental offices in the same area (35-44-year-olds; n = 401). All the subjects were clinically investigated. RESULTS: During the 1991-95 war, all four cantons were affected by the migration of population. The population per dentist ratio considerably increased in three cantons. In 6-year-olds, the average dmft (+/-SD) was 4.9 +/- 4.0, and 86% of the children were affected with dental caries. The average DMFT of 12-year-olds was 6.2 +/- 3.9. On the average, 94% of the 12-year-olds were affected with dental caries. Mean DMFT of adult clients was 15.1 +/- 7.0. Almost every adult (98%) was affected with dental caries. CONCLUSIONS: The dental status in postwar BH is rather poor and the mean DMFT in all investigated age groups may be considered high. The detrimental effect of 1991-95 war on social conditions and the health care system should be considered in explaining such poor dental health. Despite the limitations, the presented data may be used to assess the treatment needs, assure the visibility for dental issues in BH, and help the west European countries to plan dental services for refugees from BH.

Adult↗