Telomere length and its relationship with chronic diseases - New perspectives for periodontal research

Objective: The ageing process is accompanied by a variety of cellular modifications, and telomere shortening is a common finding. Large epidemiological studies have reported an association between shorter telomere length in peripheral leukocytes and several inflammatory diseases of the elderly including diabetes, atherosclerosis and, recently, periodontitis. The primary aim of this study was to critically discuss available evidence regarding the potential mechanisms relating shorter telomeres to periodontitis. Design: A narrative literature review was performed to report evidence relating shorter telomeres to the ageing process and inflammation. Then, we searched MEDLINE (1950 to May 2012) and ISI WEB OF SCIENCE (1950 to May 2012) databases for the combination of the terms 'telomere' and 'periodontitis'. Results: Although these associations suggest a possible role of telomere attrition in the onset or evolution of chronic inflammatory diseases, only two studies addressed the relationship between telomere length and periodontitis. Conclusion: We suggest that the chronic inflammatory burden observed in people with chronic periodontitis could represent the driver of telomere shortening. However, further evidence is needed to confirm whether inflammation is the cause or the consequence of the shorter leukocyte telomere length observed in people with periodontitis. © 2012 Elsevier Ltd. All rights reserved.

Histological and immunohistochemical analyses of the chronology of healing process after immediate tooth replantation in incisor rat teeth

Dental tissues have special characteristics, and its regenerative capacity is noteworthy. However, understanding the circumstances that lead to regeneration is challenging. In this study, the chronology of the healing process after immediate replantation of rat incisor teeth was examined by histological and immunohistochemical analyses within a 60-day period. Thirty-six male Wistar rats had their maxillary right incisors extracted and replanted after 15min in saline storage. The rats were sacrificed immediately 3, 7, 15, 28, and 60days after replantation. The histological analysis showed rupture of the periodontal ligament and formation of a blood clot, which started being replaced by a connective tissue after 3days. At 7days, the gingival mucosa epithelium was reinserted and areas of root resorption could be seen. At 15days, the periodontal ligament was repaired. At 3days, the pulp presented an absence of the odontoblast layer, which started being replaced by a connective tissue. This tissue suffered gradual calcification, filling the root canal at 28 and 60days. The root ends were closed. The immunohistochemical analysis revealed greater expression of OP, OPG, and RANK proteins in the initial periods (0 and 3days), while TRAP expression predominated at 28 and 60days (P<0.05). In conclusion, in delayed tooth replantation, there is great new bone formation activity in the earlier periods of the repair process, while a predominance of bone resorption and remodeling is observed in the more advanced periods. © 2012 John Wiley & Sons A/S.

Effects of vaccination against reproductive diseases on reproductive performance of lactating dairy cows submitted to AI

Four experiments evaluated the effects of vaccination against bovine herpesvirus-1 (BoHV-1), bovine viral diarrhea virus (BVDV), and Leptospira spp. on reproductive performance of lactating dairy cows without (experiments 1, 2, and 3) or with previous vaccination against these diseases (experiment 4). Cows were assigned to a fixed-time AI protocol (FTAI; d -11 to 0) in all experiments, as well as AI 12. h upon estrus detection in experiment 3. Pregnancy status was determined with transrectal ultrasonography on d 30 and 71 (d 60 for experiment 3) after AI. Pregnancy loss was considered in cows pregnant on d 30 but non-pregnant on the subsequent evaluation. In experiment 1, 853 cows received (VAC) or not (CON) vaccination against BoHV-1, BVDV, and Leptospira spp. at the beginning of the FTAI (d -11) and 30. d after AI. Pregnancy loss was reduced (P=0.03) in VAC cows compared with CON. In experiment 2, 287 cows received VAC or CON 30. d prior to (d -41) and at the beginning (d -11) of the FTAI. Pregnancy rates on d 30 and 71 were greater (P≤0.03) in VAC cows compared with CON. In experiment 3, 1680 cows with more than 28. d in milk were randomly assigned to receive VAC or CON with doses administered 14. d apart, and inseminated within 15-135. d after the second dose. Pregnancy rates on d 30 and 60 were greater (P≤0.02) in VAC cows compared with CON. In experiment 4, 820 cows received (REVAC) or not (CON) revaccination against BoHV-1, BVDV, and Leptospira spp. at the beginning of the FTAI protocol (d -11). Pregnancy rates and loss were similar (P≥0.54) between treatments. Hence, vaccinating naïve cows against BoHV-1, BVDV, and Leptospira spp. improved reproductive efficiency in dairy production systems, particularly when both doses were administered prior to AI. © 2013 Elsevier B.V.

Influence of convergence angle of tooth preparation on the fracture resistance of Y-TZP-based all-ceramic restorations

Objective: To investigate the influence of the convergence angle of tooth preparation on the fracture load of Y-TZP-based ceramic (YZ-Vita YZ) substructure (SB) veneered with a feldspathic porcelain (VM9-Vita VM9). Methods: Finite element stress analysis (FEA) was performed to examine the stress distribution of the system. Eighty YZ SB were fabricated using a CAD-CAM system and divided into four groups (n = 20), according to the total occlusal convergence (TOC) angle: G6-6° TOC; G12-12° TOC; G20-20° TOC; and G20MOD-20° TOC with modified SB. All SB were veneered with VM9, cemented in a fiber reinforced epoxy resin die, and loaded to failure. Half of the specimens from each group (n = 10) were cyclic fatigued (106 cycles) before testing. Failure analysis was performed to determine the fracture origin. Data were statistically analyzed using Anova and Tukey's tests (α = 0.05). Results: The greatest mean load to fracture value was found for the G20MOD, which was predicted by the FEA. Cyclic fatigue did not significantly affect the load of fracture. Catastrophic failure originating from the internal occlusal surface of the SB was the predominant failure mode, except for G20MOD. Significance: The YZ-VM9 restorations resisted greater compression load than the usual physiological occlusal load, regardless of the TOC angle of preparations. Yet, the G20MOD design produced the best performance among the experimental conditions evaluated. © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Simultaneity of the anthropometric markers of adiposity and chronic diseases in women

Aim. The aim of this paper was to investigate the relationship between the accumulation of different anthropometric indicators and the prevalence of some chronic diseases in women over 40 years of age. Methods. The sample was comprised of 562 women between 40 and 95 years of age (64.5 ± 11.4) attended by the research projects were carried out in two cities in southeastern Brazil. Anthropometric measurements were taken: weight, height, waist circumference, hip circumference, and the values of BMI and WHR were later calculated. The referenced morbidity questionnaire was also applied, based on the Standard Health Questionnaire (SHQ), which analyzes the presence of degenerative chronic diseases in the adult population. For the statistical treatment, the chi-square and binary logistic regression tests were performed, with significance set at 5%. Results. The relationship between three changes in the anthropometric indicators and the greater incidence of diseases continued significant for hypertension (OR=3.77 [95% CI: 2.14-6.65], =P=0.001), and for endocrine and metabolic diseases (OR=2.59 [95%: 1:47 to 4:32], =P=0.001), regardless of the effects of age and physical activities. Conclusion. The simultaneity of body fat indicators is more strongly associated with the prevalence of some chronic diseases (hypertension, endocrine, and metabolic), relative to the individualized use of anthropometric indicators.

Nanotechnology-based drug delivery systems for treatment of hyperproliferative skin diseases - a review

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Expanding the spectrum of PTH1R mutations in patients with primary failure of tooth eruption

Objectives: Primary failure of tooth eruption (PFE) is a rare autosomal-dominant disease characterized by severe lateral open bite as a consequence of incomplete eruption of posterior teeth. Heterozygous mutations in the parathyroid hormone 1 receptor (PTH1R) gene have been shown to cause PFE likely due to protein haploinsufficiency. To further expand on the mutational spectrum of PFE-associated mutations, we report here on the sequencing results of the PTH1R gene in 70 index PFE cases. Materials and methods: Sanger sequencing of the PTH1R coding exons and their immediate flanking intronic sequences was performed with DNA samples from 70 index PFE cases. Results: We identified a total of 30 unique variants, of which 12 were classified as pathogenic based on their deleterious consequences on PTH1R protein while 16 changes were characterized as unclassified variants with as yet unknown effects on disease pathology. The remaining two variants represent common polymorphisms. Conclusions: Our data significantly increase the number of presently known unique PFE-causing PTH1R mutations and provide a series of variants with unclear pathogenicity which will require further in vitro assaying to determine their effects on protein structure and function. Clinical relevance: Management of PTH1R-associated PFE is problematic, in particular when teeth are exposed to orthodontic force. Therefore, upon clinical suspicion of PFE, molecular DNA testing is indicated to support decision making for further treatment options. © 2013 Springer-Verlag Berlin Heidelberg.

Induction of ankylosis in the incisor for orthodontic tooth movement in rats

Background/Aim: The present research evaluated the induction of ankylosis and the eruption rate in rat incisors, with the aim of achieving stable anchorage for orthodontic tooth movement (OTM) of the molars. Material and methods: Fifteen male Wistar rats were used. In the Experimental group, the right superior incisor of each animal was extracted, denuded of the PDL and the dental papilla, and reimplanted. The Control group was the left superior incisors. The eruption rate was measured at 7, 10, 12, 14, and 16 days after replantation. NiTi closed springs with a 50cN release force were installed for additional 9 days, and the eruption rate was determined. Then, the rats were sacrificed, and ankylosis was examined by microscopic analysis. Differences with P < 0.01 were defined as statistically significant. Results: The eruption rates were 0 and 0.39 mm day-1 in the Experimental group and Control group, respectively. All incisors of the Experimental group showed ankylosis according to histological analysis. Conclusions: The methodology used to induce ankylosis in this study was effective for anchoring the incisors during the OTM of rat molars, eliminating the undesirable effects consequent to continuous eruption. © 2013 John Wiley & Sons A/S.

Effects of LED-laser hybrid light on bleaching effectiveness and tooth sensitivity: A randomized clinical study

The study evaluated the effectiveness and the sensitivity of in-office tooth bleaching with the use of a hybrid photo-activation system composed by LEDs and lasers. 40 patients, both genders, aged 18 through 25 years, were randomly distributed into two treatment groups: group I, 35% hydrogen peroxide, with a total bleaching time of 135 min divided into three sessions, and group II, 35% hydrogen peroxide and photo-thermal catalysis by an LED-laser system (300 mW cm-2), for a total bleaching time of 72 min divided into three sessions. The treatment efficiency was measured by reflectance spectroscopy and sensitivity by a visual analog scale (VAS). The final luminosity value (ΔL), color variation (ΔE) and sensitivity (S) resulting from the treatments were analyzed by the generalized estimating equations method (GEEs), and Bonferroni post hoc multiple comparisons at 5% significance. The two groups presented similar colors (ΔE) and luminosities (ΔL) after treatment. Group I presented a greater sensitivity index (37.6 ± 5.9%) compared to group II (11.1 ± 3.3%), statistically significant at p < 0.05. The use of LED-laser hybrid light, as a catalyst of the bleaching agents, showed a significant decrease of provoked tooth sensitivity and a treatment time reduced by 53%, with the same aesthetic results as without a light source. © 2013 Astro Ltd.

Prevalence of deciduous tooth erosion in childhood

Objectives: The objective of this study was to estimate the prevalence of deciduous tooth erosion and to identify possible associations with sex, age and toothbrushing frequency in children aged 4-6 years. Methods: The sample was drawn from attendants (n = 7058) of 57 public preschools in a Brazilian city. Tooth wear index was used to evaluate erosion. Descriptive statistical analysis consisted of the calculation of the prevalence of dental erosion; chi-squared and Fisher's exact tests were performed to verify the association between dental erosion and sex, age and toothbrushing frequency. Results: Two thousand and seven hundred and fifty-nine preschool students were examined. Deciduous tooth erosion was observed in 0.6% of children and its incidence did not differ between sexes. The highest prevalence was observed in children aged 6 years (58.3%) and the most affected sextants were the fourth (22.86%) and sixth (20.00%), indicating that lingual and occlusal tooth surfaces were most frequently involved. The degree of involvement was classified as incipient in 54.29% of children and moderate in 45.71%. The significance level was set at 5%. No association was found between erosion and sex, age or toothbrushing frequency. Conclusions: The prevalence of deciduous tooth erosion was low in Brazilian children, and this disorder is not considered a public health problem in this part of the population. © 2013 John Wiley & Sons A/S.

Effect of antimicrobial photodynamic therapy on periodontally infected tooth sockets in rats

The aim of the present study was to evaluate the antimicrobial effect of antimicrobial photodynamic therapy (aPDT) in alveolar treatment of areas with induced periodontitis. Thirty male Wistar rats were subjected to ligature-induced periodontal disease (PD) in the first left inferior molars, while the right side molars did not receive ligatures. After 7 days of PD evolution, ligatures were removed from the left side, and the first left and right mandibular molars were extracted. Afterwards, animals were divided into groups according to the following treatments: control (C)-no treatment; mechanical debridement (MD)-mechanical debridement and irrigation with saline solution; and aPDT-mechanical debridement, irrigation with toluidine blue O (TBO), and 1 min of laser irradiation (GaAlAs, 660 nm, 30 mW, 32 J/cm2, 60 s). Ligatures were removed and samples of the alveolar content after extraction and after each treatment were collected for microbial processing by real-time polymerase chain reaction with specific primers for Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Treponema denticola. Data were submitted to statistical analysis by multiple comparison tests (McNemar test; p < 0.05). T. denticola was not found in the collected samples. A. actinomycetemcomitans and P. gingivalis were found in ligature samples. Tooth socket samples without periodontitis induction presented lesser microbial charge than samples with induced periodontitis (p < 0.05). aPDT significantly reduced A. actinomycetemcomitans levels on the left side (p < 0.05). It was concluded that aPDT was an effective antimicrobial treatment for tooth sockets in areas affected by induced periodontitis. © 2013 Springer-Verlag London.

Orthodontic force increases interleukin-1β and tumor necrosis factor-α expression and alveolar bone loss in periodontitis

Background: The present study aims to evaluate the effects of orthodontic movement (OM) on the periodontal tissues of rats with ligature-induced periodontal disease. Methods: Eighty-eight rats were divided into four groups: 1) negative control (sham operated); 2) periodontal disease; 3) OM; and 4) periodontal disease followed by OM (OMP). Rats were sacrificed 3 hours or 1, 3, or 7 days after OM commencement. Bone volume fraction (BVF) and bone mineral density (BMD) were assessed in hemimaxillae by microcomputed tomography analysis. Expression of the proinflammatory cytokines interleukin (IL)-1β and tumor necrosis factor (TNF)-α were evaluated in gingival samples by quantitative polymerase chain reaction and enzyme-linked immunosorbent assay, and in the furcation region by immunohistochemistry analysis (IHC). Results: The OMP group had lower BVF and BMD levels compared to the other groups at day 7 (P <0.05). Maximum messenger ribonucleic acid expression of both cytokines was observed in the OMP group at day 1 (P <0.05). In the same period, all proteins were expressed in high levels for all test groups compared to the control group. The number of cells positive for IL-1β and TNF-α by IHC was highest in the OMP group at day 1, with progressive reduction thereafter. Conclusion: The results suggest that OM acts synergistically with periodontal disease in periodontal breakdown through upregulation of proinflammatory cytokines.

The role of cytokines in inflammatory bone loss

Chronic inflammatory processes close to bone often lead to loss of bone in diseases such as rheumatoid arthritis, periodontitis, loosened joint prosthesis and tooth implants. This is mainly due to local formation of bone resorbing osteoclasts which degrade bone without any subsequent coupling to new bone formation. Crucial for osteoclastogenesis is stimulation of mononuclear osteoclast progenitors by macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor-κB ligand (RANKL) which induces their differentiation along the osteoclastic lineage and the fusion to mature, multinucleated osteoclasts. M-CSF and RANKL are produced by osteoblasts/ osteocytes and by synovial and periodontal fibroblasts and the expression is regulated by pro- and anti-inflammatory cytokines. These cytokines also regulate osteoclastic differentiation by direct effects on the progenitor cells. In the present overview, we introduce the basic concepts of osteoclast progenitor cell differentiation and summarize the current knowledge on cytokines stimulating and inhibiting osteoclastogenesis by direct and indirect mechanisms. © Informa Healthcare USA, Inc.

Effect of the treatment of root surface-adhered necrotic periodontal ligament with propolis or fluoride in delayed rat tooth replantation

Objectives: The purpose of this study was to evaluate the application of 15 % propolis and 2 % acidulated-phosphate sodium fluoride solutions on the root surface-adhered necrotic cemental periodontal ligament in delayed tooth replantation. Materials and methods: Thirty Wistar rats (Rattus norvegicus, albinus) had their right upper incisor extracted and maintained in dry storage for 60 min. After this period, the dental papilla, enamel organ, and pulp tissue were removed, and the animals were randomly assigned to three groups: group I = immersion in saline for 10 min; group II = immersion in a 2 % acidulated-phosphate sodium fluoride solution for 10 min; and group III = immersion in a 15 % propolis and propylene glycol solution for 10 min. The root canals were filled with a calcium hydroxide paste and the teeth were replanted. Results: Inflammatory resorption, replacement resorption, and ankylosis were observed in all groups without a statistically significant difference (p > 0.05) among them. Conclusions: Under the tested conditions, the application of fluoride or propolis on root surface-adhered necrotic periodontal ligament did not favor the healing process in delayed tooth replantation. © 2013 Springer-Verlag Berlin Heidelberg.