Omega-3 and Omega-6 Fatty Acids Act as Inhibitors of the Matrix Metalloproteinase-2 and Matrix Metalloproteinase-9 Activity.

Polyunsaturated fatty acids have been reported to play a protective role in a wide range of diseases characterized by an increased metalloproteinases (MMPs) activity. The recent finding that omega-3 and omega-6 fatty acids exert an anti-inflammatory effect in periodontal diseases has stimulated the present study, designed to determine whether such properties derive from a direct inhibitory action of these compounds on the activity of MMPs. To this issue, we investigated the effect exerted by omega-3 and omega-6 fatty acids on the activity of MMP-2 and MMP-9, two enzymes that actively participate to the destruction of the organic matrix of dentin following demineralization operated by bacteria acids. Data obtained (both in vitro and on ex-vivo teeth) reveal that omega-3 and omega-6 fatty acids inhibit the proteolytic activity of MMP-2 and MMP-9, two enzymes present in dentin. This observation is of interest since it assigns to these compounds a key role as MMPs inhibitors, and stimulates further study to better define their therapeutic potentialities in carious decay.

Concentración de la enzima AST (aspartato aminotransferasa) en dientes sometidos a fuerzas ortodónticas intrusivas / Enzyme concentration AST (aspartate transaminase) teeth in orthodontic forces under intrusive

Introducción: Reportes en la literatura describen, como las fuerzas ortodónticas aplicadas durante los movimientos dentales conllevan a reacciones pulpares, alteraciones y molestias en un tratamiento de ortodoncia. La aspartato aminotransferasa (AST) es una enzima catalogada como un indicador de necrosis celular; sin embargo, es necesario evaluar su actividad en dientes sometidos a las diferentes fuerzas que se aplican durante un tratamiento ortodóntico. Objetivo: Comparar las concentraciones de aspartato aminotransferasa en tejido pulpar de dientes sometidos a fuerzas ortodónticas intrusivas y dientes libre de fuerzas. Método: Se realizó un estudio cuasi-experimental de boca dividida en 34 premolares superiores procedentes de 20 sujetos que requerían extracción de los mismos para fines ortodónticos. 20 premolares fueron expuestos por 48 horas a fuerzas intrusivas (75 g/fuerza). Los dientes contralaterales fueron usados como grupo control. Se extrajo el tejido pulpar y se midió la concentración de AST. Se tuvo en cuenta una significancia estadística de p<0,05. Resultados: Al realizar las comparaciones de las concentraciones de la enzima en ambos grupos no se encontró una diferencia estadísticamente significativa (p= 0,436). El grupo control mostró una concentración promedio de 1,78±1,13 U/mg mientras que los premolares expuestos a fuerzas intrusivas reportaron una media de 1,94±1,2 U/mg. Conclusión: La actividad de la AST a nivel del tejido pulpar no tiene variación significativa al inducir movimientos intrusivos con fuerzas aproximadas de 75 g/fuerza en la muestra estudiada

Background: Reports in the literature describe as orthodontic forces applied during dental movements lead to pulp reactions, alterations and discomfort in orthodontic treatment. Aspartate aminotransferase (AST) is an enzyme classified as an indicator of cell necrosis; However, it is necessary to evaluate their activity in teeth subjected to various forces applied during orthodontic treatment. Objective: To compare aspartate aminotransferase concentrations in teeth pulp tissue subjected to intrusive orthodontic forces and forces free teeth. Method: A quasi-experimental study of mouth divided into 34 premolars from 20 subjects requiring removal thereof for orthodontic purposes was performed. 20 premolars were exposed for 48 hours to intrusive forces (75 g/force). Contralateral teeth were used as control group. the pulp tissue was removed and the concentration of AST was measured. statistical significance of p <0.05 was taken into account. Results: When making comparisons of enzyme concentrations in both groups not a statistically significant difference (p= 0.436) was found. The control group showed an average concentration of 1.78±1.13 U/mg while the premolars exposed to intrusive forces reported an average of 1.94±1.2 U/mg. Conclusion: AST activity level does not vary pulp tissue by inducing movements intrusive forces approximate 75 g/force

Immunohistochemical analysis of matrix metalloproteinase-13 in human caries dentin.

The immunoexpression profile of matrix metalloproteinase-13 was investigated for the first time in dentin of human caries and healthy teeth. Twelve permanent premolars (10 caries and 2 sound) were decalcified in ethylenediaminetetraacetic acid and processed for embedding in paraffin wax. Sections 3-4 µm in thickness were cut and processed for immunohistochemistry. A mouse monoclonal anti-metalloproteinase-13 antibody was used for localisation using an immunoperoxidase technique. Dentinal immunoreactivity was detected in all teeth; it was weak in sound teeth and strong close to the caries area. These in vivo findings suggest a role for metalloproteinase-13 in the development and progression of adult human dental tissue disorders.

Metabolic changes of human dental pulp after rapid palatal expansion.

OBJECTIVES: To investigate rapid palatal expansion (RPE)-induced metabolic changes in human dental pulp by measuring the expression and activity of aspartate aminotransferase (AST). METHODS: mRNA and protein levels of AST in human dental pulp were measured by quantitative real-time polymerase chain reaction and Western blot, respectively. Furthermore, the activity of AST was measured by a full automatic biochemical analyzer. RESULTS: AST mRNA and protein levels were found to be expressed in normal dental pulp. Moreover, the expression of AST was increased significantly after 14 days of RPE and then decreased at 1 month in retention. Three and 6 months after RPE, the AST expression level was gradually decreased to its baseline level. Similarly, AST activity was significantly elevated after 14 days of RPE, which was then down-regulated at 1 month in retention but was still kept at a higher level as compared with the control group. The enzymatic activity of AST was slowly decreased to its baseline level at 3 and 6 months in retention. CONCLUSIONS: These results showed that significant reversible metabolic changes occurred in dental pulp during RPE, which revealed the high capacity of the pulp tissue for adaptation to this orthopedic method.

Tissue response during self-ligating treatment.

INTRODUCTION: Orthodontic tooth movement is characterized by tissue reactions, which consist in an inflammatory response in periodontal ligament, depending on the forces applied. Self-ligating brackets are able to minimize the sliding resistance and to reduce the forces necessary to move a tooth, with a better tissue response. OBJECTIVES: The purpose of this study was to evaluate the activity of the lactate dehydrogenase (LDH) in gingival crevicular fluid (GCF) during orthodontic tooth movement using self-ligating brackets. MATERIALS AND METHODS: Forty patients were selected and treated with two kinds of self-ligating brackets, Quick 2.0 and Smart Clip, and superelastic or thermoactive archwires. Patients' lower arches were bonded and GCF was collected at one side for each tooth at baseline, one hour after bonding and on the 7(th), 28(th) and 42(nd) day. Test teeth were 4.1, 4.3 and 4.5. Control teeth were 1.1, 1.3 and 1.5. Samples were analyzed with a specific assay for LDH activity. RESULTS: The statistical analysis showed no significant differences in the LDH activity between test and control teeth in the selected groups. CONCLUSIONS: There are no significant differences, in terms of tissue response, between superelastic and thermoactive archwires.

Effects of intrusive force on selected determinants of pulp vitality.

OBJECTIVE: To determine the activity of aspartate aminotransferase (AST) in the pulp of orthodontically intruded teeth and to test the sensitivity of these teeth by means of electrical pulp testing (EPT). MATERIALS AND METHODS: The study sample consisted of 21 healthy subjects who needed extraction of first premolars for orthodontic reasons. In every subject, one premolar included in a 0.016''- 0.022'' stainless steel spring from the first molar and loaded by the force was regarded as a test tooth. The magnitude of the intrusive tipping force for every tooth was calculated with the use of ANSYS 10.0 software. The contralateral premolar was used as a control tooth. After 7 days, the spring was removed, and EPT was applied to test and control teeth. The teeth were extracted, and the dental pulp was removed. AST activity in the pulp was determined spectrophotometrically at 20 degrees C. RESULTS: Estimated mean AST activity values ranged from 0.572 +/- 0.097 U/mg in the test teeth to 0.348 +/- 0.053 U/mg in the control teeth (P < .01). The EPT test showed significant differences between test and control teeth (P < .001). The mean estimated magnitude of the intrusive tipping force was 61 +/- 4.5 g. CONCLUSION: Seven days of orthodontic intrusion can cause metabolic changes in the pulp expressed by increased AST activity. The increased threshold in the pulp reaction to EPT indicates changes in the neural response of the pulp.

MMP-2, MMP-9, and iNOS expression in human dental pulp subjected to orthodontic traction.

OBJECTIVE: To test the hypothesis that some metalloproteinases (MMP-2, MMP-9) and inducible nitric oxide synthetase (iNOS) enzymes in dental pulp samples do not vary when subjected to orthodontic treatment. MATERIALS AND METHODS: Human dental pulps were taken from male and female patients (N=10; age 10-14 years). A straight wire technique was used with nickel-titanium or steel archwires. The increase of pressure applied on teeth was gradual. Five patients were subjected to premolar extractions after 14 months of treatment and one after 24 months. Samples were Bouin-fixed, paraffin-embedded, and afterwards processed for immunohistochemistry using anti-MMP-2, anti-MMP-9, and anti-iNOS antibodies. RESULTS: A reduction of MMP-2, MMP-9, and iNOS expression occurred in treated samples. This became more evident with increased treatment time. CONCLUSION: The hypothesis is rejected. The reduction of expression of those proteins revealed a time-dependent relationship.

Role of the friction free distalize appliance (2FDA)PAT in the molar distalization: photoelastic analysis and alkaline-phosphatase (ALP) activity on first molar and bicuspid.

Maxillary molar distalization is an increasingly popular option for the resolution of Class II malocclusions. This study describes the effects of one particular molar distalizing appliance, the Friction Free Distalize Appliance (2FDA), in a sample of 20 consecutively treated and growing patients to verify the osteoblastic activity in the compression and traction sites of both the molars and the bicuspids when used as the anchorage teeth. The 2FDA appliances were constructed utilizing a Nickel Titanium open coil spring of 200 gr force in order to distalize the maxillary first molar. The reaction force was controlled utilizing the principle of low/free friction. The results show that the resin around the root of the bicuspid did not discolour at all, which indicates an absence of a force load. On the other hand, on the molar, the resin around the root of the molar became discoloured due to the fact that an orthodontic force was involved with the tooth. To better understand whether the quantity of force that reached the tooth was able to produce osteoblastic recruitment in the sites of tension of the molar and the bicuspid, we quantified an enzyme, the alkaline phosphatase (ALP), present. This measurement allowed us to verify a regular increase of the ALP on the site of molar traction. We also elaborated a mathematical model to evaluate the quantity of force of reaction that produces the device on the bicuspid. Such force results as being 8.34 grams which equals half the pressure of the capillaries of the parodontal ligament (18 grams). The 2FDA appliance compares favourably with other intra-oral distalization devices for the resolution of patients with Class II malocclusions, and is the only distalizing appliance that does not determine osteoclastic/osteoblastic recruitment on the anchorage tooth.

Alkaline phosphatase activity in dental pulp of orthodontically treated teeth.

INTRODUCTION: The aim of this study was to examine alkaline phosphatase (ALP) activity in the dental pulp of orthodontically treated teeth. METHODS: Sixteen healthy subjects (mean age 17.0 +/-1.6 years) who required extraction of 4 first premolars for orthodontic reasons participated. One maxillary first premolar subjected to orthodontic force was the test tooth. The contralateral first premolar, bracketed but not subjected to mechanical stress, was the control tooth. After a week of treatment, the first premolars were extracted and the dental pulp removed from the teeth. ALP activity was determined spectrophotometrically and the results expressed as units/liter per milligram of pulp tissue [U/(L x mg)]. RESULTS: ALP activity was 89 +/- 26 U/(L x mg) in the test teeth and 142 +/- 33 U/(L x mg) in the control teeth. The difference between the groups was statistically significant (P < .01). CONCLUSIONS: Orthodontic treatment can lead to significant early-phase reduction in ALP activity in human dental pulp tissue.

Aspartate aminotransferase activity in pulp of orthodontically treated teeth.

This study examines the aspartate aminotransferase activity in the pulp of orthodontically treated teeth. Seventeen healthy male and female subjects (ages: 14.5-19.6; mean 16.8 +/- 1.6 years) who needed extraction of the maxillary first premolars for orthodontic reasons were enrolled in the study. One randomly chosen maxillary first premolar, included in a straight-wire fixed orthodontic appliance and supporting orthodontic force, was considered as the test tooth. The contralateral first premolar, included in the orthodontic appliance but not subjected to mechanical stress, was used as the control tooth. After a week of treatment, the dental pulp tissues were extracted from both experimental teeth. Aspartate aminotransferase activity was significantly elevated in the test teeth as compared with the control teeth. These results demonstrate that in the early phases of treatment, orthodontic force application to the teeth can lead to significant metabolic changes in the pulp of these teeth.

Prolyl-hydroxylase activity in odontoblasts from bovine incisor and premolar teeth.

Odontoblasts of incisor and premolar teeth showed high prolyl-hydroxylase (EC 1.14.11.2; proline, 2-oxoglutarate dioxygenase) activity, but the activities in other regions of these dental pulps were low. These results suggest that these odontoblasts are concerned with the biosynthesis and processing of dentine collagen.