Objective: The aim of this study was to evaluate the impact of an estrogen‐deficient state and its therapies (estrogen and calcitonin administration) upon bone loss resulting from an experimental ...periodontitis.
Methods: Fifty‐eight Wistar rats were divided into four groups: group 1 (n = 15): sham operated; group 2 (n = 15): ovariectomized; group 3 (n = 14): ovariectomized plus calcitonin administration; group 4 (n = 14): ovariectomized plus estrogen administration. Twenty‐one days after ovariectomy or sham surgeries, the ligature was randomly placed. Sixty days later, the animals were killed and the specimens routinely processed. In addition, serum levels of alkaline phosphatase and calcium were assessed.
Results: Intergroup analysis revealed that an estrogen‐deficient state significantly increased bone loss resulting from periodontitis and that such an effect could not be prevented either by estrogen or calcitonin administration (0.34 ± 0.13, 0.65 ± 0.06, 0.63 ± 0.19, 0.67 ± 0.28 for groups 1, 2, 3 and 4, respectively). Furthermore, an estrogen‐deficient state presented a direct effect on the alveolar bone regardless of plaque accumulation and this effect may be significantly reduced by estrogen administration (p < 0.05). Serum analysis demonstrated a higher bone turnover for the animals with estrogen deficiency, and estrogen therapy restored bone metabolism.
Conclusion: Estrogen administration may prevent the direct effect of an estrogen‐deficient state on alveolar bone; however, neither estrogen nor calcitonin administration could prevent this effect when associated with a response to a plaque‐related inflammatory process.
Photofunctionalization mediated by ultraviolet (UV) light seems to be a promising approach to improve the physico-chemical characteristics and the biological response of titanium (Ti) dental ...implants. Seeing that photofunctionalization is able to remove carbon from the surface, besides to promote reactions on the titanium dioxide (TiO
) layer, coating the Ti with a stable TiO
film could potentialize the UV effect. Thus, here we determined the impact of UV-photofunctionalized mixed-phase (anatase and rutile) TiO
films on the physico-chemical properties of Ti substrate and cell biology. Mixed-phase TiO
films were grown by radiofrequency magnetron sputtering on commercially pure titanium (cpTi) discs, and samples were divided as follow: cpTi (negative control), TiO
(positive control), cpTi UV, TiO
UV (experimental). Photofunctionalization was performed using UVA (360 nm - 40 W) and UVC (250 nm - 40 W) lamps for 48 h. Surfaces were analyzed in terms of morphology, topography, chemical composition, crystalline phase, wettability and surface free energy. Pre-osteoblastic cells (MC3T3E1) were used to assess cell morphology and adhesion, metabolism, mineralization potential and cytokine secretion (IFN-γ, TNF-α, IL-4, IL-6 and IL-17). TiO
-coated surfaces exhibited granular surface morphology and greater roughness. Photofunctionalization increased wettability (p < 0.05) and surface free energy (p < 0.001) on both surface conditions. TiO
-treated groups featured normal cell morphology and spreading, and greater cellular metabolic activity at 2 and 4 days (p < 0.05), whereas UV-photofunctionalized surfaces enhanced cell metabolism, cell adhered area, and calcium deposition (day 14) (p < 0.05). In general, assessed proteins were found slightly affected by either UV or TiO
treatments. Altogether, our findings suggest that UV-photofunctionalized TiO
surface has the potential to improve pre-osteoblastic cell differentiation and the ability of cells to form mineral nodules by modifying Ti physico-chemical properties towards a more stable context. UV-modified surfaces modulate the secretion of key inflammatory markers.
The aim of this study was to determine the impact of standard methods for processing decalcified highly mineralized tissues on RNA yield and quality from microdissected samples.
Rat mandibles were ...fixed with either formalin-based or ethanol-based fixatives, decalcified in 20% ethylenediaminetetraacetic acid solution for 15 days, and embedded in paraffin. Transversal sections of the molars were mounted on membrane glass slides for laser capture microdissection. Unfixed frozen liver samples were used as controls to determine the impact of fixatives, decalcification and paraffin embedding on RNA integrity and recovery after sample preparation, and laser microdissection. Total RNA was obtained from periodontal ligament and fresh-frozen liver; RNA quality was assessed by Bioanalyzer, and 5 ng of total RNA was used for cDNA synthesis followed by gene expression analyses by polymerase chain reaction using 3 sets of primers for glyceraldehyde 3-phosphate dehydrogenase.
Data analysis demonstrated that all fixed samples presented some level of RNA fragmentation as compared with fresh-frozen samples (P<0.05). Samples fixed with Protocol (10% formalin) showed the least RNA fragmentation as compared with other fixatives (P<0.05), and biologically useful RNA was extracted even from microdissected samples with a minimum RNA Integrity Number of 1.5. Moreover, RNA fragments up to 396 bp were assayable by reverse transcriptase-polymerase chain reaction, although short-targeted fragments as 74 bp were more consistently amplified.
Although variable levels of RNA fragmentation should be expected, gene expression analysis can be performed from decalcified paraffin-embedded microdissected samples, with the best results obtained for short-targeted fragments around 70 bp.
Parathyroid hormone intermittent administration has been considered to treat bone mass decrease in osteoporotic individuals. The present study evaluates whether PTH can affect alveolar bone loss in ...ovariectomized rats, since estrogen deficiency has been proposed as a risk factor for periodontal disease.
Thirty female rats were set in groups: ovariectomized (Ovx) and Sham operated. Ovx were divided in two groups: Ovx-PTH (1–34) treated and Ovx, which received vehicle. After 1 week, cotton ligature was placed around one lower first molar of all animals to induce periodontal disease. Ovx treated received PTH doses of 40
μg/kg, three times a week for 30 days. After that, the animals were sacrificed, the mandibles extracted, X-rayed and samples prepared for histological evaluation. Histomorphometry was performed using image analyzer software. Scanning electron microscopy (SEM) of the tibias was also performed in all animals to evaluate possible changes in bone structure caused by the estrogen deficiency. Optical densities of the radiographs were measured by aluminum step-wedge equivalent thickness.
Histomorphomery indicated the anabolic PTH effect in ovariectomized rats with significant inhibition of periodontitis manifestation (
p
<
0.05) thus neutralizing the periodontitis inductor effects. The photo densitometry showed a lower mandibular optical density in the ovariectomized group that did not receive PTH (
p
<
0.05). SEM image confirmed the early effect of estrogen deficiency in osseous tissue and PTH anabolic effect.
PTH systemic intermittent administration was able to reduce alveolar bone loss in ovariectomized rats, despite the presence of a periodontal disease inductor and estrogen deficiency.
The purpose of this study was to clinically evaluate an absorbable collagen membrane (Bio‐Gide
®
) and a nonabsorbable polytetrafluoroethylene membrane (PTFE), associated or not with bone grafts, for ...the treatment of ligature‐induced peri‐implantitis defects in dogs. The bilateral mandibular premolars were removed from 5 2‐year‐old mongrel dogs. After 3 months of healing, 3 titanium implants were placed on each side of the mandible. Experimental peri‐implantitis was induced after abutment connection. Ligatures and abutments were removed after 1 month and the bone defects were randomly assigned to one of the following treatments: DB: debridement alone; GBR+BG‐I: debridement plus PTFE membrane associated with mineralized bone graft (Bio‐Oss
®
); GBR+BG‐II: debridement plus collagen membrane (Bio‐Gide
®
) associated with mineralized bone graft; GBR‐I: debridement plus PTFE membrane; GBR‐II: debridement plus collagen membrane; BG: debridement plus mineralized bone graft. The peri‐implant bone defects were measured before and 5 months after treatment. Results showed the greatest percentage of vertical bone fill for GBR+BG‐II (27.77±14.07) followed by GBR‐II (21.78±16.19), BG (21.26±6.87), GBR+BG‐I (19.57±13.36), GBR‐I (18.86±10.63) and DB (14.03±5.6). However, the values were not statistically significant (ANOVA, contrast
F
test,
P
=0.612). Within the limits of the present investigation, it can be concluded that no difference was detected among treatments.
Résumé
Le but de cette étude a été d’évaluer cliniquement une membrane en collagène absorbable (Bio‐Guide
®
) et une en téflon non‐absorbable (PTFE) associées ou non à des greffons osseux pour le traitement de lésions paroïmplantites induites par ligature chez le chien. Les prémolaires inférieures ont été avulsées chez cinq bâtards de deux ans. Après trois mois de guérison, trois implants en titane ont été placés de chaque côté de la mandibule. La paroïimplantite expérimentale a été induite après la connection des piliers. Les ligatures et les piliers ont été enlevés après un mois et les lésions osseuses ont été réparties de manière randomisée vers un des traitements suivants: DB: nettoyage seul, GBR+BG‐I: nettoyage plus Bio‐Oss plus membrane en téflon, GBR+BG‐II: nettoyage plus Bio‐Gide
®
plus greffe d’os minéralisé, GBR‐I: nettoyage plus membrane en téflon, GBR‐II: nettoyage plus membrane collagène, BG: nettoyage plus greffe d’os minéralisé. Les lésions osseuses paroïmplantaires ont été mesurées avant et cinq mois après le traitement. Les résultats ont montré le plus grand pourcentage de remplissage osseux vertical pour GBR+BG‐II (27,8±14,1) suivi de GBR‐II (21,8±16,2), BG (21,3±6,9), GBR+BG‐I (19,6±13,4), GBR‐I (18,9±10,6) et DB (14,0±5,6). Cependant ces valeurs n’étaient pas statistiquement significatives (ANOVA, test
F
contraste,
P
=0,612). Dans les limites de l’étude présente, il peut être conclu qu’aucune différence n’a été détectée entre ces traitements.
Zusammenfassung
Das Ziel dieser Studie war es, klinisch eine resorbierbare Kollagenmembran (Bio‐Gide
®
) und eine nicht resorbierbare Polytetrafluoroethylen‐Membran (PTFE) mit oder ohne Füller (Knochentransplantat) zur Behandlung von ligatureninduzierten Periimplantitisdefekten von Hunden zu untersuchen. Bei 5 zweijährigen Bastarden wurden beidseitig die Unterkieferprämolaren extrahiert. Drei Monate später, nach abgeschlossener Heilung, implantierte man auf jeder Seite des Unterkiefers drei Titanimplantate. Nach dem Aufsetzen der Sekundärteile wurde eine experimentelle Periimplantitis induziert. Einen Monat später wurden Ligaturen und Sekundärteile entfernt und die Knochendefekte zufällig einer der folgenden Behandlungsarten zugeführt: DB: nur Debridement; GBR+BG‐I: Debridement, Defektfüllung mit einem mineraliserten Knochentransplantat (Bio‐Oss
®
) und Defektdeckung mit einer PTFE‐Membran; GBR+BG‐II: Debridement, Defektfüllung mit einem mineralisierten Knochentransplantat und Defektdeckung mit einer Kollagen‐Membran (Bio‐Gide
®
); GBR‐I: Debridement und Defektdeckung mit einer PTFE‐Membran; GBR‐II: Debridement und Defektdeckung mit einer Kollagen‐Membran; BG: Debridement und Defektfüllung mit einem mineralisierten Knochentransplantat; Die periimplantären Knochendefekte wurden vor der Behandlung und 5 Monate später vermessen. Die Resultate zeigten, dass die grösste prozentuale vertikale Knochenauffüllung bei der Gruppe GBR+BG‐II (27.77±14.07) stattfand, gefolgt von der Gruppe GBR‐II (21.78±16.19), BG (21.26±6.87), GBR+BG‐I (19.57±13.36), GBR‐I (18.86±10.63) und DB (14.03±5.6). Die Ergebnisse waren jedoch nicht statistisch signifikant (ANOVA, Kontrast
F
Test,
P
=0.612). Mit den gewählten Vorgaben konnte man also keine Unterschiede zwischen den verschiedenen Behandlungen feststellen.
Resumen
La intención de este estudio fue evaluar clínicamente una membrana reabsorvible de colágeno (Bio‐Guide
®
) y una membrana no reabsorvible de politetrafluoroetileno (PTFE), asociada o no con injertos óseos, para el tratamiento de defectos de periimplantitis inducida por ligaduras en perros. Se extrajeron los premolares mandibulares bilateralmente de cinco perros mongrel de dos años de edad. Tras tres meses de cicatrización se colocaron tres implantes de titanio en cada lado de la mandíbula. Se indujo periimplantitis experimental tras la conexión de los pilares. Las ligaduras y los pilares se retiraron después de un mes y los defectos óseos fueron asignados aleatoriamente a uno de los siguientes tratamientos: DB: sólo desbridamiento; GBR+BG‐I. desbridamiento más membrana de PTFE asociada con injerto óseo mineralizado (Bio‐Oss
®
); GBR+BG‐II: desbridamiento más membrana de colágeno (Bio‐Gide
®
) asociado con injerto óseo mineralizado; GBR‐I: desbridamiento más membrana de PTFE; GBR‐II: desbridamiento más membrana de colágeno; BG: desbridamiento más injerto óseo mineralizado. Los defectos óseos se midieron antes y cinco meses después del tratamiento. Los resultados mostraron un mayor porcentaje de relleno óseo vertical para GBR+GB‐II (27.77±14.07) seguido por GBR‐II (21.78±16.19), BG (12.26±6.87), GBR+BG‐I (19.57±13.36), GBR‐I (18.86±10.63) y DB (14.03±5.6). De todos modos los valores no fueron estadísticamente significativos (ANOVA, test de contraste
F
,
P
=0.612). Dentro de los limites de la presente investigación se puede concluir que no se detectaron diferencias entre los tratamientos.
Background: The aim of the present study was to histometrically evaluate bone healing in the absence of bone defects and in the presence of surgically created bone defects treated by guided bone ...regeneration at oxidized and turned implant surfaces.
Methods: Three months after dental extractions, standardized buccal dehiscence defects (height: 5 mm; width: 4 mm) were surgically created following implant site preparation in the mandible of 10 dogs. Oxidized‐surface implants (OSI) and turned‐surface implants (TSI) were inserted bilaterally, and the bone defects were treated by guided bone regeneration. After 3 months of healing, the animals were sacrificed, blocks were dissected, and undecalcified sections were obtained and processed for histometric analysis. The percentage of bone‐to‐implant contact (BIC) and bone density (BD) was evaluated inside the threads on the buccal (regenerated bone) and lingual sides (pristine bone) of the implants. Data were evaluated using two‐way analysis of variance (P <0.05).
Results: New bone formation could be observed in OSI and TSI in the region of the defect creation. The BIC values observed in OSI for pristine and regenerated bone were 57.03% ± 21.86% and 40.86% ± 22.73%, respectively. TSI showed lower values of BIC in pristine bone (37.39% ± 23.33%) and regenerated bone (3.52% ± 4.87%). The differences between OSI and TSI were statistically significant. BD evaluation showed no statistically significant differences between OSI and TSI in pristine and regenerated bone.
Conclusion: The oxidized implant surface promoted a higher level of BIC than the turned implant surface at pristine and regenerated bone.
Background: Smoking has been associated with periodontitis severity and is considered a risk factor for its development. It has been reported that matrix metalloproteinase (MMP) produced by host ...cells plays a major role in periodontal tissue destruction. Thus, the present study tested, in rats, the hypothesis that local increased levels of MMP‐2 would be associated with the enhanced periodontitis‐related bone loss after intermittent cigarette smoke inhalation (CSI).
Methods: Twenty‐seven adult male Wistar rats were used. A ligature was placed around one of the mandibular first molars of each animal and they were randomly assigned to the following control (N = 13) or CSI (N = 14) group. Sixty days later, the animals were sacrificed, the gingival tissues harvested, and the specimens processed for decalcified sections. Extracts from the gingival tissues were prepared and assayed for MMP‐2 expression.
Results: Intergroup comparisons (unligated sites) showed that CSI might directly affect alveolar bone (0.16 ± 0.03 mm2 versus 0.24 ± 0.09 mm2 for non‐smokers and smokers, respectively; P = 0.001). Moreover, CSI significantly enhanced bone loss resulting from experimental periodontitis (0.64 ± 0.36 mm2 versus 1.50 ± 0.50 mm2 for non‐smokers and smokers, respectively; P <0.05). In addition, zymography demonstrated that CSI also enhanced both MMP‐2 levels and activity in the gingival tissues around ligated teeth.
Conclusion: Within the limits of the present investigation, it can be assumed that the effect of CSI on MMP‐2 levels and activity may account for the increased periodontitis progression rate observed in smokers. J Periodontol 2004;75:995‐1000.
Objectives: The aim of this study was to clinically detect the immediate effect of root instrumentation with curettes and ultrasonic scalers on clinical attachment level.
Material and Methods: Twelve ...subjects with moderate chronic periodontitis, presenting probing depths of 3.5–6.5 mm on anterior teeth, upper and/or lower, were selected. Teeth were randomly assigned to one of the following groups: US group – scaled with an ultrasonic scaler; and CC group – scaled and planed with 5–6 Gracey curettes. The selected teeth were probed with a computerized electronic probe, guided by an occlusal stent and subjected to scaling and root planing. Immediately following instrumentation, teeth were probed again. The difference between relative attachment level (RAL) immediately before and after instrumentation was considered trauma from instrumentation.
Results: Intra‐group analysis revealed statistically significant differences between RAL immediately before and after instrumentation in both groups (0.77±0.51 for US group; and 0.73±0.41 for CC group, p<0.0001). However, inter‐group analysis did not show statistically significant difference in trauma from instrumentation caused by the two different instruments (p=0.816).
Conclusions: Within the limits of this study, it was concluded that root instrumentation causes a mean immediate attachment loss of 0.75 mm, and that instrumentation with either curettes or ultrasonic scalers do not seem to reduce significantly the trauma from of instrumentation produced.
Objectives: The aim of this study was to investigate the influence of cementum removal on periodontal repair.
Material and Methods: Forty subjects with chronic periodontitis and presenting, at least, ...two proximal sites in anterior teeth (upper or lower) with probing depth 5 mm were selected. After oral hygiene instructions and ultrasonic supragingival instrumentation, the subjects were randomly assigned for one of the following groups: CIC, scaled with Gracey curettes; CIUS, scaled with ultrasonic device; CDC, calculus deattachment with Gracey curettes and brushing with saline solution; and CDUS, calculus deattachment with ultrasonic device and brushing with saline solution. Full‐thickness flaps were reflected and the instrumentation was performed with a clinical microscope. Probing depth (PD), relative gingival margin level (RGML) and relative attachment level (RAL) were registered at five experimental periods: baseline and 30, 60, 90 and 120 days postoperative.
Results: All the approaches were able to markedly reduce the PD values from the baseline to the other evaluation periods (p<0.0001). The increase in RGML values was statistically significant only for the CDUS group. There were no statistically significant differences between the baseline and postoperative values in all groups for the RAL changes. The changes in RAL were statistically significant only among the groups CDC and CDUS (p<0.0001).
Conclusion: The conventional scaling and root planing and the calculus deattachment were effective in reducing the probing depth values, regardless of the instrumentation method.
