Research Article Changes of Substance P in the Crevicular Fluid in...

Hindawi Publishing CorporationThe Scientific World JournalVolume 2013 Article ID 896874 6 pageshttpdxdoiorg1011552013896874

Research ArticleChanges of Substance P in the Crevicular Fluid in relation toOrthodontic Movement Preliminary Investigation

Luca Levrini1 Paola Sacerdote2 Sarah Moretti2 Silvia Panzi1 and Alberto Caprioglio1

1 Dipartimento di Scenze Chirugiche e Morfologiche Universita degli Studi dellrsquoInsubria 2110 Varese Italy2 Dipartimento di Scienze Farmacologiche e Biomolecolari Universita degli Studi di Milano 20129 Milano Italy

Correspondence should be addressed to Luca Levrini lucalevriniuninsubriait

Received 9 January 2013 Accepted 7 March 2013

Academic Editors S G Alessandro P Cozza and A Geramy

Copyright copy 2013 Luca Levrini et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Substance P (SP) is a tachykinin released fromboth the central and the peripheral endings of primary afferent neurons and functionsas a neurotransmitter As a transmitter signaling pain substance P is involved in nociception and is an extremely potent vasodilatorWe found several studies about this neuropeptide especially in relation to parodontology and a few orthodontic reviews This isbecause in the past the importance of this neuropeptide in dental element undergoing periodontal inflammation was observedTheaims of the present pilot study was to investigate whether the substance P was present in gingival crevicular fluid in dental elementsundergoing orthodontic treatment with Invisalign technique compared to teeth belonging to the same series but not undergoingorthodontic movement We analysed gengival crevicular fluid (GCF) collected from four young subjects using a paper cone for atime of 60 seconds The results showed that SP is present in the gengival sulcus in elements undergoing orthodontic forces duringtreatment with Invisalign technique and not in the control teeth During the literature analysis we have found a lot of papersdescribing involvement of SP in periodontitis and inflammatory diseases but further studies are needed in order to demonstratethe role of this neuropeptide during teeth movement

1 Introduction

The mechanical stress applied to a tooth due to orthodontictreatment induces an inflammatory reaction which leads tothe remodelling of periodontal tissues resulting in toothmovement Since the periodontal ligament (PDL) and thedental pulp are well innervated and contain numerousreceptors for noxious stimuli it is conceivable that neu-rotransmitters in particular substance P could mediatethe biological response to mechanical stress applied to theteeth during orthodontic treatment [1] It is clear from theliterature [2] that all orthodontic procedures such as the useof elastic separators [3] the placement of braces and theapplication of orthopaedic forces cause pain in patients It isalso known that nonremovable devices produce more painthan removable or functional devices and there is a poorcorrelation between the intensity of the applied force and thepain experiencedThe experiences reported bymany patientsafter placement of the device are often described as sensationsof pressure tension and teeth painThere is no demonstrated

relationship between age sex and psychological and culturalperception of pain following the placement of an orthodonticappliance The correlation between the psychological well-being of patients and the perception of orthodontic pain wasprovedwithout doubtWe know from the published literaturethat women feel more pain than men and adolescents reporthigher levels of pain than preteens and adults [1] SubstanceP is a neuropeptide known to be deputed to nociceptivetransmission signal [4ndash6]The history of this molecule beganin 1931 when scholars Von Euler and Gaddum isolated thesubstance from the brain and intestine of horses Severalstudies [7] have stressed the importance of substance P asa mediator of pain and inflammation In particular we canobserve an increase in the concentration of the neuropeptidein the pulp of patients suffering from caries pulpitis andgranulomas and during movement of the dental elementsconsequent to orthodontic treatment [7] Substance P ispresent in the sulcular fluid from this drawing its concen-tration is assessable The purpose of this pilot study was toverify the experimental feasibility and observe the change in

2 The Scientific World Journal

the concentration of substance P in dental elements under-going orthodontic forces during treatment with Invisaligntechnique The choice of this type of device was due to theneed of something that can predict the presence or absence oftooth movement Different studies have already analyzed thedifferent concentrations of SP comparing differentmultibandsystems with the aim to reduce inflammation and pain[8 9] Main articles were identified by a specific searchMEDLINE using appropriate keywords (eg substance Pand dental movement or orthodontic movement) which wasthen refined manually browsing the reference lists of articlesretrieved and with the addition of other relevant documentsaccording to the authorsrsquo knowledge of the field

11 Teeth Movement Each tooth is attached to the surround-ing alveolar bone and at the same time separated from itby a robust support structure of collagen the periodontalligament (PDL) Its main component is represented by a setof parallel collagen fibers which are placed between cementand a relatively robust bone surface the lamina dura Thespace of the PDL (about 05mm) is occupied by the tangleof fibers but there are two other important components ofthe periodontal ligament the cellular component consists ofa variety of mesenchymal cells and tissue fluids Althoughnot intensely vascularized the PDL has vessels and cellsof the blood system There are also unmyelinated nervefibers appointed to the perception of pain and complexreceptor associated with the pressure and proprioceptiveinformation [10ndash12] During normal chewing teeth andperiodontal structures are subject to heavy forces [13] andintermittent ranging from 1 to 2 kg when you chew soft foodsthat can reach up to 50 kg for harder foods When the toothis subjected to loads of this type its rapid displacement inspace of the PDL is prevented by the presence of the fluidby its nature incompressible The force is transmitted therebyto the walls of the alveolar process causing a deflexion of thesupport structures often not appreciable Only a small partof the fluid contained in the space of the PDL is ejectedduring the first second of solicitation pressure However ifthe pressure will be maintained on the tooth this fluid maybe expelled and the tooth is moved in space of the PDL inturn compressed against the walls adjacent bone The painwill normally be perceived in 3ndash5 seconds after applicationof a heavy force a sign that the liquid was squeezed outTooth movement induced by application of orthodonticforces (orthodontic tooth movement (MDO)) is based onthe remodelling of the dental and periodontal tissues [14]Two interrelated processes involved in MDO are flexion ofthe alveolar bone and remodelling of periodontal tissuesincluding dental pulp periodontal ligament (PDL) the alve-olar bone and the gum [15] When we apply a continuousand light force to the tooth we can observe a reduction ofblood flow through the PDL partially compressed this occursas soon as the fluids are pushed outside the periodontalspace following the displacement of the tooth in the alveolarbone (in a few seconds) Within a few hours the chemicalchanges occurred induce a differentmodel of cellular activityIn animal experiments increased levels of adenosine 31015840 51015840

Figure 1 Invisalign ClinCheck allows to predict dental movementwith a very high precision comparing every single element This isan example of drowning the first premolar coloured in blue is thecontrol site and the second premolar is the test site The blue colorrepresents the position of the tooth before movement and the whiteone is the element subjected to dental flaring

Figure 2The picture shows the flaringmovement in a lower incisor

monophosphate (cAMP) the ldquosecond messengerrdquo of manyfunctions involved in cellular differentiation were foundthis occurs approximately 4 hours after the application ofcontinued pressure [16] The same amount of time wasnecessary in humans to get a first response to the applicationof removable devices In fact if these devices are worn for lessthan 4ndash6 hours a day they will not induce any orthodonticeffect [17]

2 Materials and Methods

Thesample examined consisted of all the subjects treatedwithInvisalign technique at the Dental Clinic of the University ofInsubria Among these through the analysis of theClinCheckInvisalign (Figure 1) four patients were chosen where thetooth movement to be achieved was a simple flaring thatwas an inclination of a degree of the dental element to thefornix (Figure 2) considering the long axis as a guide to themovement (experimental sample) at the same time there hadto be an element in the same dental arch and contralateralwithout movement (control sample) Three of these couples

The Scientific World Journal 3

Figure 3 Example of drawings in the first upper premolar The lipswere moved with a cotton wool roll Probing depth was collectedwith a paper cone from the mesial portion of the teeth

were in the incisors series three belonged to premolar andtwo molars Among these four young female patients wereselected aged respectively 13 years and 10 monthsndash19 yearsand 11 monthsndash17 years and 6 months and 15 years and 7months with a molar ratio of first class canine ratio of firstclass It was also verified that the subjects examined showed(1) a general good health (2) the lack of antibiotic therapy inthe past six months (3) no use of anti-inflammatory drugsduring the month preceding the study (4) periodontal healthwith generalized and physiological probing depth of 2mm(5) no radiographic evidence of bone loss (6) crowding inone or both jaws (7) a bleeding index of zero and (8) absenceof caries and tartar Informed consent was obtained from thepatients and parents before the study Before the beginning oftherapy all patients had an appointment of oral hygiene withultrasonic instruments Probing depth presence of plaqueand bleeding were evaluated on both arches The drawings(Figure 2) were performed both on the dental element thatwould have been the subject of orthodontic force compressedby the movement of flaring and on the motionless one Thesites selected for GCF sampling were isolated using cottonwool rolls and a saliva ejector Supragingival plaque wascarefully removed using a curette We took four samplesfrom one subject probing depth from the four lower incisors(element 32 and 41 were test and 31 and 42 control) Fromthe second patient we analysed six elements from premolarseries (elements 14 and 15 and 45 as control elements24 25 and 34 as test) and two elements from the molarseries (46 as control and 36 as test) From patient three westudied two elements from the molar series (16 as test and26 as control) From patient four we analysed two elementsfrom incisors series (32 as test and 31 as control) Beforeintroducing the paper cone (Periopaper Harco Tustin CAUSA) in the gingival sulcus it has been dried with warm airfor 10 seconds The instrument was introduced taking careto avoid mechanical damage for a time of 60 seconds alwaysin the mesial portion of element The drawing of sulcularfluid was carried out using paper cones with a diameter of35 times 10

minus5m (Figure 3) The cones were introduced in thegingival sulcus of the element for a time of thirty secondsand then stored in a fridge at minus30∘C Elution of SP from eachpaper strip was performed by centrifugation of the samples

Table 1 SP levels in crevicular gengival fluid of four patients In thecolumn on the left side we had specified the number of patient andthe dental element number using the FDI system of nomenclatureldquoTrdquo test tooth ldquoCrdquo control site In the right column there is the SPmeasurement expressed in pg

Dental element Measure (pg)PZ1 31 C 54PZ1 32 T 164PZ1 42 C 42PZ1 41 T 110PZ2 14 C 44PZ2 24 T 57PZ2 15 C 47PZ2 25 T 39PZ2 46 C 40PZ2 36 T 138PZ2 45 C 35PZ2 34 T 188PZ3 26 C 34PZ3 16 T 251PZ4 31 C 39PZ4 32 T 122

in 04mL of 002M Tris-HCL buffer (pH 75) for 30 minutesand the supernatant was collected for SP measurement [18]The amount of SP in each sample was determined by enzymelinked immunosorbent assay (ELISA) with a commerciallyavailable kit (RampD Systems Minneapolis MN USA) Theresults are expressed as the total amount per 60 s GCFsamples

3 Results

The average value of SP concentration in the GCF drawingsobtained from the experimental samples was 134 pg plusmn 68(mean plusmn SD) while that of the control group was 42 pg plusmn 06(Table 1) The levels of SP detected in control elements werealways very low at the limit of detectionThe teethmovementincreased the levels of the neuropeptide in all patientsStatistical evaluation of results with Studentrsquos 119905-test showedthe presence of a significant difference between experimentalsamples and controls (119875 lt 001)

4 Discussion

Recently the role of SP in the modulation of pain andinflammation in dental procedures has attracted much atten-tion However the studies examining the modulation ofthis neuropeptide in orthodontic movements are still scarceAlthough we are aware of the limited number of patients inour pilot study the data obtained seem to confirm an involve-ment of SP during this type of procedures In particular ourpilot study is the first study to examine the SP concentrationin the GCF after the Invisalign procedure Interestingly arecent study carried out by Miller et al [19] has shownthat adults treated with Invisalign aligners felt less pain and


fewer negative impacts on their lives during the first week oforthodontic treatment compared to those treated with fixedappliances In this prospective longitudinal study carriedout on 60 adult orthodontic patients (33 with Invisalignaligners 27 with fixed appliances) pain was assessed usinga daily diary to measure the impact of treatment in terms offunctional psychosocial and pain related results A diary wascompleted for seven consecutive days in order tomeasure theimpact of orthodontic treatment The baseline mean valuesdid not differ between groups for pain reports or overallquality of life impact During the first week of treatmentthe subjects in the Invisalign group reported fewer negativeimpacts on overall quality of life The Invisalign groupalso recorded less impact in each quality of life subscaleevaluated (functional psychosocial and pain-related) Thevisual analog scale pain reports showed that subjects in theInvisalign group experienced less pain during the first weekof treatment The subjects in the fixed appliance group tookmore pain medications than those in the Invisalign group atdays 2 and 3 Yamaguchi et al demonstrated that the levels ofSP and IL-1 in GCF are increased by orthodontic movement[9] The study was carried out by Yamaguchi et al [9] byusing Damonrsquos technique They showed that there was nosignificant difference in respect to the control site in themeanvolume of SP during the therapy between the groups whereconventional braces were utilized comparing to self-ligatingattachment and the control site [20] The same authors [18]analysed nine adult orthodontic patients treated with fixapplianceThe experimental protocol provided the extractionof a first premolar in order to allow the canine distalization(with an elastic chain) and use the contralateral element asa control group The samples SP performed after 8 24 and72 hours showed a higher concentration of substance P inthe test site than the control while the samples carried out at168 hours showed that the SP value was lower in the test sitethan control Nicolay and colleagues [1] hypothesized that theSP could mediate the biological response of the mechanicalstress applied to the teeth during orthodontic treatment andperformed a study in the cat using an immunohistochemicaltechnique They applied a force for a time ranging from1 hour to 14 days using a group of cats tipping distallythe maxillary canine Horizontal histological sections 5 120583mthick collected from frozen specimens were stained usingrabbit anti-SP polyclonal antibodies This preliminary studyshowed that the stimulation of periodontal nerve fibers bymeans of orthodontic forces may induce peripheral releaseof SP in the pulp and PDL The SP may be the initial triggerfor a biochemical cascade that leads to the activation oftarget cells in the periodontium SP can either act directlyon the target cells as a ldquofirst messengerrdquo or enhance therelease of other messengers as prostaglandins and cytokinesleading to an increase of ldquointracellular second messengersrdquoIn both cases the SP appears to play a key role in theregulation of cellular responses to mechanical forces in vivoA higher number of studies have evaluated the levels of SPand SP-related peptides in several oral diseases such as peri-odontitis and pulp inflammation Awawdeh and colleagues[21] evaluated 20 patients half of which were affected byperiodontal disease the concentrations of SP and neurokinin

A (NKA) Gingival crevicular fluid (GCF) was collected from20 subjects in three different sites the first was a healthy sitethe second presented gingivitis and the third periodontitisThe aim of the study was to investigate whether the substanceP and neurokinin A were present in gingival crevicularfluid in both periodontal health and disease and to studythe relationship with periodontal inflammation In subjectswith periodontitis there were significant increases in thelevels of SP and NKA in both sites with periodontal diseasein comparison to healthy sites Interestingly subjects withperiodontitis showed increased levels of SP also in healthysites when compared with patients without periodontaldisease Similar results were found by Alstergren et al [22]in fluid aspirated from temporomandibular jointsThe higherlevels of substance P inGCF particularly in diseased sitesmayindicate that SP has a more important role in periodontalinflammation than NKA In fact Pernow [23] reported thatthe proinflammatory potency of SP is greater than NKAThe proinflammatory effects of tachykinins may however becounterbalanced by their reparative and regulatory roles thathave only recently been elucidated SP and NKA stimulateDNA synthesis when added to cultured skin fibroblasts[24] Bartold et al [25] have shown that SP can influencehuman gingival fibroblast proliferative and synthetic activityand suggested that the action of this peptide could switchfrom a catabolic proinflammatory mode to an anabolictissue regenerative mode depending on the presence of otherfactors Tachykinins released by peripheral neurones couldnot only contribute to the inflammatory response but also actto stimulate proliferation of surrounding connective tissuecells starting a healing response in tissue SP and NKA mayhave a relationship with periodontal disease A systematicstudy of the relationship of these tachykinins and otherneuropeptides in periodontal disease may be useful for fur-ther clarifying the mechanisms that regulate the health andperiodontal disease Hanioka and colleagues [18] observed48 subjects with periodontal disease at an advanced stagewith gingival inflammation and shallow or moderately deeppocket Gingival crevicular fluid was collected at one siteper subject from the mesial surface of the palatal aspect ofmaxillary canines or premolars The experimental site wasselected according to the worst score of gingival inflam-mation The level of inflammation and destruction of thesupporting tissues was moderate In the present study 35of the samples had SP levels below the detection limit ofELISA This may partly be due to having many sites in thepresent study slightly involved in periodontal inflammationThe SP level was also significantly correlated with indicatorsof host response The results of Hanioka and colleaguesshowed that SP level in GCF may have a potential as anindicator of periodontal inflammation and the host responseAwawdeh and colleagues [21] examined a group consistingof 54 subjects who had been diagnosed with irreversiblepulpitis against one or more elementsThis was the first studyto quantify neuropeptides in GCF comparing painful teethand the healthy contralateral No teeth with pocket probingdepths of more than 3mmwere included Gingival crevicularfluid was collected from the mesial interproximal gingivalcrevice of each tooth diagnosed with irreversible pulpitis and


scheduled to receive endodontic therapy Significantly moreof SP values were detected in GCF test element than thecontralateral control element After endodontic medicationthe amount of SP decreased in 17 (81) sites it remainedthe same in a single site and it was slightly increased inthree (14) sites One week after pulp removal there was nomeasurable SP in the GCF from seven (33) initially painfulteeth The concentration of SP also decreased as a resultof treatment In contrast the amount and concentration ofSP in GCF from contralateral and adjacent teeth did notchange significantly following pulp removal from the painfultooth The presence of SP and NKA in GCF of painful andnon-painful teeth raises the question of their origin It ispossible that the increased release of the tachykinins frompeptidergic nerve endings in the inflamed dental pulp ismirrored by an increase in activity of similar fibres in theperiodontium This could result in higher concentrations ofneuropeptides in the GCF not only from painful teeth butalso from adjacent teeth A significant decrease was foundin the levels of SP in GCF after pulp removal while nodifference was evident in the contralateral elements Theauthors explained the results saying that there are increasesin neuropeptide levels particularly of the tachykinins SP andNKA in GCF associated with irreversible pulpitis in painfulhuman teeth Furthermore there was a marked decrease inSP levels after pulp removal At present it is not possible toexplain the exact mechanisms responsible for the high levelsof neuropeptides in GCF in painful teeth

5 Conclusions

During the literature analysis we have realized that severaldifferent basal levels of SP have been detected and this makesit difficult to compare the results obtained However despitethis limitation it can be affirmed that in the crevicularfluid elements undergoing orthodontic force an appreciableamount of SP is present while its level in control subjectscannot often be evaluated Whereas the involvement ofSP in periodontitis and inflammatory diseases is now wellaccepted further studies are needed in order to demonstratethe role of this neuropeptide during teeth movement

Conflict of Interests

The authors declare that they have no conflict of interestsdirectly relevant to this study

References

[1] O Nicolay J Shanfeld Z Davidovitch and K Alley ldquoSPimmunoreactivity in the dental pulp and periodontium duringtooth movementrdquo Annals of the New York Academy of Sciencesvol 632 pp 452ndash454 1991

[2] V Krishnan ldquoOrthodontic pain from causes to managementmdasha reviewrdquo The European Journal of Orthodontics vol 29 no 2pp 170ndash179 2007

[3] C Giannopoulou A Dudic and S Kiliaridis ldquoPain discomfortand crevicular fluid changes induced by orthodontic elastic

separators in childrenrdquo Journal of Pain vol 7 no 5 pp 367ndash3762006

[4] J D Richardson and M R Vasko ldquoCellular mechanismsof neurogenic inflammationrdquo Journal of Pharmacology andExperimental Therapeutics vol 302 no 3 pp 839ndash845 2002

[5] S Harrison and P Geppetti ldquoSubstance Prdquo International Journalof Biochemistry andCell Biology vol 33 no 6 pp 555ndash576 2001

[6] D G Snijdelaar R Dirksen R Slappendel and B J P CrulldquoSubstance Prdquo The European Journal of Pain vol 4 no 2 pp121ndash135 2000

[7] C K Park J H Bae H Y Kim et al ldquoSubstance P SensitizesP2X3 in nociceptive trigeminal neuronsrdquo Journal of DentalResearch vol 89 no 10 pp 1154ndash1159 2010

[8] P Sacerdote and L Levrini ldquoPeripheral mechanisms of dentalpain the role of substance Prdquo Mediators of Inflammation vol2012 Article ID 951920 6 pages 2012

[9] M Yamaguchi T Takizawa R Nakajima R Imamura and KKasai ldquoThe damon system and release of substance P in gingivalcrevicular fluid during orthodontic tooth movement in adultsrdquoWorld Journal of Orthodontics vol 10 no 2 pp 141ndash146 2009

[10] P Scott M Sherriff A T DiBiase and M T CobourneldquoPerception of discomfort during initial orthodontic toothalignment using a self-ligating or conventional bracket systema randomized clinical trialrdquoThe European Journal of Orthodon-tics vol 30 no 3 pp 227ndash232 2008

[11] S H Z Ariffin Z Yamamoto Z Z Abidin R M AbdulWahab and A W Z Ariffin ldquoCellular and molecular changesin orthodontic tooth movementrdquo Scientific World Journal vol11 pp 1788ndash1803 2011

[12] Y Ren and A Vissink ldquoCytokines in crevicular fluid andorthodontic tooth movementrdquo European Journal of Oral Sci-ences vol 116 no 2 pp 89ndash97 2008

[13] V Krishnan and Z Davidovitch ldquoCellular molecular andtissue-level reactions to orthodontic forcerdquoThe American Jour-nal of Orthodontics and Dentofacial Orthopedics vol 129 no 4pp 469e1ndash469e32 2006

[14] W R Proffit H W Fields Jr and D M Sarver ContemporaryOrthodontics Elsevier Milano Italy 2000

[15] Z Davidovitch and J L Shanfeld ldquoCyclic AMP levels in alveolarbone of orthodontically treated catsrdquo Archives of Oral Biologyvol 20 no 9 pp 567ndash574 1975

[16] C Dolce J S Malone and T T Wheeler ldquoCurrent conceptsin the biology of orthodontic tooth movementrdquo Seminars inOrthodontics vol 8 no 1 pp 6ndash12 2002

[17] M Yamaguchi M Yoshii and K Kasai ldquoRelationship betweensubstance P and interleukin-1120573 in gingival crevicular fluidduring orthodontic tooth movement in adultsrdquo The EuropeanJournal of Orthodontics vol 28 no 3 pp 241ndash246 2006

[18] T Hanioka K Takaya Y Matsumori R Matsuse and SShizukuishi ldquoRelationship of the Substance P to indicators ofhost response in human gingival crevicular fluidrdquo Journal ofClinical Periodontology vol 27 no 4 pp 262ndash266 2000

[19] K B Miller S P McGorray R Womack et al ldquoA comparisonof treatment impacts between Invisalign aligner and fixedappliance therapy during the first week of treatmentrdquo TheAmerican Journal of Orthodontics and Dentofacial Orthopedicsvol 131 no 3 pp 302e1ndash302e9 2007

[20] L Bolamperti PMontanari L Levrini AMacchi A Tagliabueand A Caprioglio ldquoTissue response during self-ligating treat-mentrdquo Progress in Orthodontics vol 13 no 2 pp 109ndash116 2012


[21] L A Awawdeh F T Lundy G J Linden C Shaw J GKennedy and P J Lamey ldquoQuantitative analysis of substanceP neurokinin A and calcitonin gene-related peptide in gingivalcrevicular fluid associated with painful human teethrdquo TheEuropean journal of oral sciences vol 110 no 3 pp 185ndash1912002

[22] P Alstergren A Appelgren B Appelgren S Kopp T Lun-deberg and E Theodorsson ldquoCo-variation of neuropeptide Ycalcitonin gene-related peptide substance P and neurokininA in joint fluid from patients with temporomandibular jointarthritisrdquo Archives of Oral Biology vol 40 no 2 pp 127ndash1351995

[23] B Pernow ldquoResearch on tachykinins clinical trendsrdquo in Sub-stance P and Neurokinins pp 373ndash379 Springer New York NYUSA 1987

[24] J Nilsson A M von Euler and C J Dalsgaard ldquoStimulation ofconnective tissue cell growth by substance P and substance KrdquoNature vol 315 no 6014 pp 61ndash63 1985

[25] P M Bartold A Kylstra and R Lawson ldquoSubstance P animmunohistochemical and biochemical study in human gin-gival tissues A role for neurogenic inflammationrdquo Journal ofPeriodontology vol 65 no 12 pp 1113ndash1121 1994

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Volume 2014

Stem CellsInternational



Enzyme Research



Microbiology


the concentration of substance P in dental elements under-going orthodontic forces during treatment with Invisaligntechnique The choice of this type of device was due to theneed of something that can predict the presence or absence oftooth movement Different studies have already analyzed thedifferent concentrations of SP comparing differentmultibandsystems with the aim to reduce inflammation and pain[8 9] Main articles were identified by a specific searchMEDLINE using appropriate keywords (eg substance Pand dental movement or orthodontic movement) which wasthen refined manually browsing the reference lists of articlesretrieved and with the addition of other relevant documentsaccording to the authorsrsquo knowledge of the field

11 Teeth Movement Each tooth is attached to the surround-ing alveolar bone and at the same time separated from itby a robust support structure of collagen the periodontalligament (PDL) Its main component is represented by a setof parallel collagen fibers which are placed between cementand a relatively robust bone surface the lamina dura Thespace of the PDL (about 05mm) is occupied by the tangleof fibers but there are two other important components ofthe periodontal ligament the cellular component consists ofa variety of mesenchymal cells and tissue fluids Althoughnot intensely vascularized the PDL has vessels and cellsof the blood system There are also unmyelinated nervefibers appointed to the perception of pain and complexreceptor associated with the pressure and proprioceptiveinformation [10ndash12] During normal chewing teeth andperiodontal structures are subject to heavy forces [13] andintermittent ranging from 1 to 2 kg when you chew soft foodsthat can reach up to 50 kg for harder foods When the toothis subjected to loads of this type its rapid displacement inspace of the PDL is prevented by the presence of the fluidby its nature incompressible The force is transmitted therebyto the walls of the alveolar process causing a deflexion of thesupport structures often not appreciable Only a small partof the fluid contained in the space of the PDL is ejectedduring the first second of solicitation pressure However ifthe pressure will be maintained on the tooth this fluid maybe expelled and the tooth is moved in space of the PDL inturn compressed against the walls adjacent bone The painwill normally be perceived in 3ndash5 seconds after applicationof a heavy force a sign that the liquid was squeezed outTooth movement induced by application of orthodonticforces (orthodontic tooth movement (MDO)) is based onthe remodelling of the dental and periodontal tissues [14]Two interrelated processes involved in MDO are flexion ofthe alveolar bone and remodelling of periodontal tissuesincluding dental pulp periodontal ligament (PDL) the alve-olar bone and the gum [15] When we apply a continuousand light force to the tooth we can observe a reduction ofblood flow through the PDL partially compressed this occursas soon as the fluids are pushed outside the periodontalspace following the displacement of the tooth in the alveolarbone (in a few seconds) Within a few hours the chemicalchanges occurred induce a differentmodel of cellular activityIn animal experiments increased levels of adenosine 31015840 51015840

Figure 1 Invisalign ClinCheck allows to predict dental movementwith a very high precision comparing every single element This isan example of drowning the first premolar coloured in blue is thecontrol site and the second premolar is the test site The blue colorrepresents the position of the tooth before movement and the whiteone is the element subjected to dental flaring

Figure 2The picture shows the flaringmovement in a lower incisor

monophosphate (cAMP) the ldquosecond messengerrdquo of manyfunctions involved in cellular differentiation were foundthis occurs approximately 4 hours after the application ofcontinued pressure [16] The same amount of time wasnecessary in humans to get a first response to the applicationof removable devices In fact if these devices are worn for lessthan 4ndash6 hours a day they will not induce any orthodonticeffect [17]

2 Materials and Methods

Thesample examined consisted of all the subjects treatedwithInvisalign technique at the Dental Clinic of the University ofInsubria Among these through the analysis of theClinCheckInvisalign (Figure 1) four patients were chosen where thetooth movement to be achieved was a simple flaring thatwas an inclination of a degree of the dental element to thefornix (Figure 2) considering the long axis as a guide to themovement (experimental sample) at the same time there hadto be an element in the same dental arch and contralateralwithout movement (control sample) Three of these couples








3 Results


4 Discussion







5 Conclusions




References



































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology








3 Results


4 Discussion







5 Conclusions




References



































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology






5 Conclusions




References



































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology














Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology

Research Article Changes of Substance P in the Crevicular Fluid in...

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