Pro-Matrix - Case Study

ApproximatingSurfaceMatrixBandforDentisttoUseforPatients

UniversityofWisconsin-Madison BiomedicalEngineeringDesign400

October20th,2021

Client: Dr.DonaldTipple-NakomaDental

Advisor: Dr.TracyJanePuccinelli

TeamMembers:

TaraBoroumand(Leader)

GraceJohnson(Communicator)

MatthewFang(BSAC)

DraesonMarcoux(BWIG)

TrevorSilber(BPAG)

Fifty-threemillionpeoplelivewithuntreatedtoothdecay,labellingcavitiesasasilentepidemic. Thisissuedisproportionatelyaffectsdisadvantagedcommunities,andunfortunately,cavitiesbecome moredifficulttorepairthelongertheyareleftuntreated[1] Untreatedtoothdecaycanleadtosevere toothpainanddiscomfort,andinsomecases,toothloss.Dentalfillingsremainthemostcommonmethod ofcombatingtoothdecay,thus,itisessentialthatfillingproceduresareoptimized.Currentmatrixbands, suchassectionalandcircumferentialbands,failtoallowconcurrentrestorationofadjacentinterproximal cavities.Theteamistaskedwithdesigningamatrixbandthatcansupportthesimultaneousfillingoftwo adjacentteethwithinterproximalcavitieswhilemaintainingpropertoothcontact Adesignhasbeen proposedthatutilizestwomatrixbandsattachedattheinterproximalregion,eachhavinghalfthe thicknessofaregularmatrixband,tosupporttheproperandflossabletoothcontact.Thisdesign incorporatesametalpiececomingoutfromthebandthatwouldaidintheplacementandremovalofthe devicewhileexertinginwardforcetomaintainatightcontactwiththetoothsurface.Theviabilityofthe devicewillbedeterminedbyfunctionalityteststhatdeterminewhetherthedesignallowsfortheproper toothcontactthatcurrentmatrixbandscreate Thisfunctionalitytestingwillrevealfurther accommodationstheteamwillneedtomaketoconfirmthedeviceisabletosupporttwoadjacent interproximalcavitiesundergoingrepair,whilemaintainingaflossabletoothcontactandreducing proceduretime

I. Introduction A.Motivation

ItisestimatedtheaverageAmericanhasthreedentalfillings,whileoneinfourAmericanshave elevenormorefillings.Althoughcavitiesareoneofthemostcommondentalprocedures,theCDCstill estimatesthataboutone-thirdofadultshaveuntreateddentalcariesthatrequirefillings[2].Dentalcaries arealsoknownastoothdecay,andtheyresultfromenamelbreakdown Thegoalofafillingistoremove thedecayedpartofthetooth,whichisreferredtoasthecavity,andfilltheareawithanenamel mimickingmaterialtopreventanyfurtherdamage[3] Pathologiesresultingfromuntreatedcavitieshave disproportionatelyaffectedblackandhispanicadults,youngeradults,andthosefromlowerincome communities.Approximately9%oftheworld’spopulationisaffectedbyuntreateddentalcaries.There hasbeenasignificantamountofevidencethattoothdiseasehasgonedowninmanycountries However, dentalcariescontinuetoaffectmanypeople,especiallychildren,whichcanleadtoprematuredentalloss [4].Anewmatrixbanddevicecouldhelpadvancethepublicdentalhealthindustrybyhelpingsimplify proceduresforpracticingdentists,makingtreatmentmoreefficientandlesscostly

B.CurrentDevices

Theearliestimplementationofmatrixbandsgenerallyrequiredminorcustomfabrication techniquessuchassoldering,scoringandcutting,orusingfusingcompounds However,preformed, adjustablebandsbecamethestandardinthelast50years[5] Preformedbandsreducethetimeto placementasstructuralmodificationsarenotnecessary,onlyforcedbending.Therearetwomaintypesof preformeddentalmatrixbands,sectionalandcircumferential[6] Sectionalmatrixbandsaremoresuited forproximalcavitiesandonlyfitaroundhalfofthetooth Theyarerequiredtobesupportedbyaringfit aswellasleveredbyawedgebetweentwoteeth.Circumferentialmatrixbandsaregenerallyusedwitha tofflemireretainerandarewrappedaroundthewholetooth Thetofflemireisabletotightentheband aroundthetoothandstillrequirestheuseofawedge.Bothoftheseareusedcommonlyinpractice although74%ofdentistspreferthesectionalbandmethod[7].Mostbandsthatarecreatedfor interproximalcavitiesuseacircumferentialmodelwhichwasnotdesiredbytheclient Thereareacouple examplesofsectionalmatrixbandmodelsbutnonearemainstaysinthemarketandsomehaveissuesthat makethemodelsundesirablefortheclient

TheTofflemire™matrixbandandretainerisacircumferentialdesignmeanttowraparounda singletoothduringaninterproximalprocedure.Thissystemisusedinconjunctionwithdentalwedgesto createabetterfitwiththegingivalsurfaceandcreatespaceintheinterproximalareaoftheteeth The bandisfirstburnishedtocreateacontouralongthebottomedgetofitbetweenthegumlineandtooth. Thenthebandisfoldedintoateardropshape,placedintotheheadoftheretainerandclampedintoplace, readyfortighteningaroundthetooth[8] Ourclientcurrentlyusesthissystem,asseeninFigure1,butis limitedbythetedioussetupandabilitytoonlyworkononetoothatatime.

ThePro-MatrixSingleUseMatrixBandfromAstekInnovation,asseeninFigure2,isa circumferentialdesignthatcombinesthetofflemireandmatrixbandintooneeasytousedevice The devicehastwokeycomponents,switchanddial,thatallowthedevicetobeusedonmanydifferenttooth sizes.Theswitchisusedtochangetheangleofthematrixbandrelativetothedevice,toallowthedevice tobeusedoneithersideofthemouthwithmaximumband-toothcontact Oncethedeviceisplaced aroundthetooth,thedialonthebottomcanbespuntotightenorloosenthematrixbandaroundthetooth Thedentistwillthenhavetoinstallawedgeunderneaththebandtoensurenomovementandtoprotect thegums

TheTriodentV3RingusedalongsidetheTriodentWave-Wedgeisadvertisedasasectional matrixsystemthatallowsforsuperiorfunctionalitycomparedtothecircumferentialband(Tofflemire) [11][12][13].However,ifthisTriodentringisusedtoseparateadjacentteethwiththeplacementoftwo matrixbands,thecontactbetweentheteethwouldnotofferoptimalcontactleadingtoalargergapthan desired

Figure1:Tofflemire MatrixBandsystem.Circumferentialmatrixbandsystemconsistingofthe proprietaryretainer(left),bands(right),andanydentalwedges(notpictured)[5]. Primary4matrixbandsizesare shownontheright

Figure2:Pro-MatrixBands.Theleftimageshowsthecoloredswitchatthetopandcoloreddialatthe bottom.Therightimageshowshowthedevicewouldinstallaroundatooth[9][10].

C.ProblemStatement

Matrixbandsareacommonlyuseddentaltoolwhichassistdentistsbycreatinganoutside contourofadecayedtooth Thiscontourmaintainsthetooth’sstructureandshapeduringrestorative procedures,suchascavityfillings Duringtypicalfillingproceduresforcavitiesoninterproximal surfaces,dentistsmustfilleachtoothseparately.Thistediousprocedureisduetomatrixbandsnotfitting adjacenttooneanotherintheinterproximalspace,asthethicknessoftwobandsexceedsthetoothcontact diameterbetweentheteeth.Theresultingprocessofplacingmatrixbandsforbothteethiscumbersome andtimeinefficient.Anewdentalmatrixbanddesignisdesiredtoalleviatetheneedtorepeatedlyplace bands Thedeviceshouldemployadual-bandsystemwithathicknesslessthanorequivalenttocurrent matrixbands,0.05mm,throughoutsuchthatthefitissecureandthebandmoldstotheappropriate convex/concavecontourofeachtooth Thefinalizedproductshouldalsomaintainthetensilestrength, about400MPa,malleability,andspaceefficiencyofcurrentmatrixbands Thematerialusedtofabricate thematrixbandmustnotcauseanyirritation,mustbebiocompatible,andmustbenon-reactivetofilling materials

II. Background A.DesignResearch

Dentalmatrixbandsaredesignedtobeplacedintheinterproximalspacebetweenatooth undergoingrestorationanditsadjacenttooth.Thebandfunctionsincreatingtheoutsidecontourforthe restorativematerialsothatthedecayedtoothmayberepairedbacktoitsoriginalshapeandstructure

Mostmatrixbandsaremadefromadeadsoftmetal,suchasstainlesssteel,whichallowsthemtobe malleableandeasilyshapedtofitavarietyoftoothsizes[14].

Theaveragecrownheightofmaxillary(upper)andmandibular(lower)teethtogetheris869mm, witharangeofmeasurementsfrom7.2mmto11.2mm.Themesiodistalcrownwidth,whichmeasures thediameterofthetoothinthedirectionfromitsmoreanterioradjacenttoothtoitsmoreposterior

Figure3:TriodentV3RingandTriodentWave-Wedge. Sectionalmatrixbandsystemconsistingof TriodentV3ring(green),TriodentWave-Wedge(purple),andsectionalmatrixband(silver)[13].

adjacenttooth,averages8.20mm,withvaluesrangingfrom5.3mmto11.4mm.Thefaciolingualcrown width,whichmeasuresthediameterofthetoothinthedirectionfromcheeksidetotongueside,averages 871mm,withvaluesrangingfrom57mmto115mm[15] Basedonthesevalues,approximationsfor toothperimeteraverage33.82mm,rangingfrom22.0mmto45.8mm.

Thethicknessofdentalmatrixbandstypicallyrangesfrom00015to0002inches,or0038to 0051millimeters[16] Thebandwidthmustfallintothesepreciserangesinorderforthedeviceto securelyfitbetweenadjacentteethwithoutexceedingthewidthoftheinterproximalspace.Correctly placedandeffectivematrixbandsarerigidagainsttheexistingtoothstructureandmaximizematrix-tooth contact,properlycontouringtotheshapeofthetooth[17] Theymustrestoreappropriatecontactwiththe adjacenttoothandbeeasilyremovableoncetherestorativematerialisset[8].Uponinsertion,dental matricesoftenrequiretheuseofretainers,rings,clips,orwedgestoholdthebandinplaceandwidenthe interproximalspace.Thesetools,however,makethepatient’smouthcrowdedandthereforemakethe restorativeproceduremoredifficultforthedentist.

ThepreviousBMEdesignteamfromlastsemesterwasabletodevelopadual-matrixband device,butmechanicalandfunctionalitytestingledtofailureandincompleteresults.Theteamdid, however,comeupwithapromisingdesignideathatcouldbefurtherdevelopedbythecurrentteam This design,the“Butterfly”design,isoutlinedin III

Preliminary Designs

B.ClientInformation

Dr.DonaldTippleisthedentistandsoleownerofNakomaDentalinMadison,WI.Hehasover 30yearsofexperienceasadentalpractitioner,specializinginpreventativecareandrestorativesolutions

C.DesignSpecifications

Thematrixbandshouldbeabletomaintainitsstructureandfunctionfromthetimeitisplacedin themouthuntilthefillingprocedureisover,upto1hour[18].Thedevicewillbesingle-use,butshould stillbesterilizablebeforeitisusedinprocedure Thebandshouldstillbemalleableandabletoshape aroundanytooth,incorporatingwedgesand/orringclampsthateffectivelyseparatetheapproximating teethbeingfilled Also,thenewdeviceshouldbeeasierandmuchlesstimeconsumingtoinstall,adjust, andusethanexistingproductsonthemarket,likethesectionalandcircumferentialmatrixbands Intermsofdimensions,thedevicethicknessshouldbeaccuratetoahundredthofamillimeter duringmanufacturetoensureitremainsbelow005mm,anacceptableinterproximalspace[16] Current matrixbandscommonlycomeinthreedifferentthicknesses:0001gauge(00254mm),00015gauge (0.0381mm),and0.002gauge(0.0508mm),themaximumacceptableinterproximalspacetomaintain toothcontact[19] Thedeviceshouldbeadjustableand/orscalabletoaccommodateallsizesofteeth whilestillmaintainingtheproperthickness.

Thematrixbandisexpectedtobemadeoutofadeadsoftmetal,meaningitisrigidinitsresting statewhilestillbeingmalleable[20] Thiswouldincludematerialssuchasstainlesssteelandaluminum Ifpossible,thematerialshouldbeabletobesanitized,allowingforamoresustainableproductthatisalso morecosteffective Forthepurposesofthisproject,thewedgewilllikelybemadeofsomesortofplastic duetotheeaseoffabrication Thebandandthewedgeshouldnotbecoloredthesameasatoothtoavoid confusionwhileoperating.Theaestheticswerenotaprioritywiththeclientanddependmoreon functionality Theremustbesafetyconsiderationswhenconsideringdesigningtheprototype Thematerial

usedtofabricatethematrixbandshouldnotcauseanyirritationtopatients(i.e.Nickel)andmustbe biocompatible.Thedevicealsomustcomewiththepropersafetylabelsandwarningstoinformusershow toproperlyhandlethedevice Thedeviceshouldmatchtheshelflifeofcurrentmatrixbands(so indefinitely),whilekeptintheproperpackagingandmustbestoredatornearroomtemperature.Along withstoragewhilenotinuse,thehumanmouthisavariableenvironmentwithbothphysical,chemical andbiologicalfactorstoconsider Thedevicemustmaintainitsintegritywhenforcedinbetweenteeth whichhaveaMohshardnessratingof5[21].Itmustalsobebluntenoughtopreventinjuryofthe, potentiallycompromised,toothandsurroundinggums Operatingtemperaturerangesfromroom temperature(~20℃)tobodytemperature(~37℃) ThemouthhasapHwitharangeof62-76 Thereare alsoavarietyofenzymesinthesalivathatthedevicemustwithstand[22].

Intermsofproduction,theproductisexpectedtobenon-reusable Thatmeansifitismade marketavailable,theproductwouldneedtobemassproducedtomeetthedemandofdentistsforevery adjacenttoothfillingprocedure.Ifthefinaldesignwereabletobesterilized,thenthedemandforthe productwouldgodowntooneperdentist Forthepurposesoftheproduct,therewilllikelybeacouple modelsproduced.Thegoalwhenplanningoutthedesignsistokeeptheproductsascosteffectiveas possiblewithoutsacrificingquality Currentmatrixbandsgoforabout50centstoadollar[23] Giventhe possiblecomplexityofourdesign,itmightbemoreexpensivetofabricatebutkeepingthepriceunder $3-5shouldbeprioritized.Thebudgetfortheprojectisexpectedtobearound$200-300giventhetesting neededtobedone

FDAapprovalisnecessaryformedicaldevices.CurrentmatrixbandsareClass1devicesas specifiedintheCodesofRegulationsTitle21,Chapter1,SubchapterH,Part872SubpartE.Theyare identifiedaslowriskdevicesthatpresentminimalpotentialforharm Ifthenewdesignutilizesthesame materialsusedbefore1976,itwouldbeexemptfrompremarketnotificationproceduresspecifiedin SubpartE.Otherwise,apremarketnotificationsubmissionwouldneedtobecompletedtotheFoodand DrugAdministrationatleast90dayspriortotheproposedintroductionoftheproduct[24] An InvestigationalDeviceExemption(IDE)wouldneedtobeobtainedtopursueclinicalstudieswiththe devicetocollectdataonsafetyandeffectivenessinsupportofthePremarketApproval(PMA)application orPremarketNotification510(k)submission ThesestudiesmustbeapprovedbytheInstitutionalReview Board(IRB)beforethestudiesbegin[24].ForthefullProductDesignSpecifications,refertoAppendix A

III. PreliminaryDesigns

A.Design1-HandcuffDesign

Figure4:HandcuffDesignSideView. Length,measuredlefttoright,shouldbeintherangeof44mmto91.6mm. Height,measuredtoptobottomexcluding“spikes”,shouldbeintherangeof7.2mmto11.2mm.Slotfittings,in

blue,aregapsinthematrixband,usedtosecurethedeviceafterinstallation Spikes,smallpointsmedialtotheslots, areusedtohelpkeepthedeviceinplaceandpreventcavitymaterialfromseepingintothegums

TheHandcuffDesignisamodificationofacircumferentialmatrixbandsothatitcanbeusedto surroundtwoadjacentteeth Thedesignconsistsofasinglebandoffairlythinwidth,00254mm,with slotfittingsoneitherendthatareslightlywider.Theideaisthatthebandwouldwraparoundthetwo targetedteethlaterally(cheekside)andcometogethermedially(tongueside)intheinterproximalspace. Thebandshouldbethinenoughtofitthroughthisspace,butiftheteetharetooclosetogetherforthe bandtofit,thedentistcanusearingtocreateatemporarygapintheteeth.However,tosavetime,the thicknessofthedevicecouldbechangedtobetterfitamajorityofinterproximalspaces.Oncethebandis inplace,eachendofthebandispulledtight Onepairoftheslotfittings(onefromeachsideoftheband) wouldthenslideoverthemiddleoftheband,completingtheloopsaroundtheteethandlockingtheband securelyinplace Toaccountformultipledifferenttoothsizes,differentlengthbandscouldbeproduced withjustafewslotsataspecifieddistancefromtheend,oronelargersizebandcouldbeproducedwitha largenumberofslotsacrossthemajorityoftheband.Thebandwouldneedtobemadeofadeadsoft metalinordertoensureitsform-fittingproperties Thebandwouldalsolikelybeonetimeusebefore needingtodisposeofit.Thebandwouldhavetobeusedintandemwithawedgeinordertoprovide moresupportindrivingmatrixbandsagainstthewallofthetooth.Fabricationofthedevicecouldbe carriedoutrelativelyeasilybyusingalasercutteronaverythinsheetofdeadsoftmetal Afewmajor drawbackstothisdeviceisthatitmayrunintosomeissueswhentryingtocreateaverytightfitaround theteethandslidingthetinyslotsaroundthethinmatrixbandmayturnouttobeverytimeconsuming

Figure5:HandcuffDesignTopView. Thehandcuffbandiswrappedaroundtwoteethwithcavities(darkholesin theteeth).Thebandisheldinplacebyplacingthecenterofthebandthroughanyoftheblueslots.Thicknessofthe bandwouldbe0.0254mm.

B.Design2-ButterflyDesign

TheButterflyDesignisasinglematrixbandthatcanbethoughtofastwosectionalmatrixbands conjoinedwheretoothcontactwilloccur Thecurvatureofeachsideofthebandwouldallowthisdesign towraparoundeachtooth Thecenterofthebutterflybandwouldhaveathicknessof00254mmto ensureafitbetweentheteeth.Toensurethecenterthickness,eachhalfofthebutterflybandwouldhavea thicknessof00127mm AsintheHandcuffDesign,thisdevicewouldalsobefabricatedfromadeadsoft metal.InstallationofthisdeviceshouldbemuchfasterandeasierthaninstallationoftheHandcuff Design,asthisdesignwouldonlyrequirethedentisttoseparatetheteethifneededandthentheband couldbeslidintoplace Oncethedeviceisinstalledbetweenthetargetteeth,twowedgesmustbeplaced betweenthegumsandthebandtohelpsecureitinplace.Thisdevicemayalsoneedtobeusedin combinationwithtworings,tosecuretheedgesofthematrixbandtotheteethandensurepropercontact topreventanycavityfillingmaterialfromseepingoutofthedeviceandintothegumsofthepatient Theseringscanbequitelargeandmayendupinhibitingthecavityfillingprocess.

Figure6:ButterflyDesignSolidworks3DModel.Thisdesignconsistsoftwosectionalmatrixbandsconjoined togetherinthemiddletoproduceabandthatslightlyresemblesabutterfly Holesinthebandwillhelptoaidthe removalofthedevice.Outsidethicknessof0.0127mm,insidethicknessof0.0254mm,andstraightlength(when thecurveofthebandisbentstraight)of33mmto687mm

Figure7:ButterflyDesigninstalled.Thishanddrawnimageshowshowthebutterflyband(darkblue)wouldsit betweenteeth(lightblue)andbeheldinplacebytwowedges(orange)

C.Design3-Butterfly+UPinchersDesign

blue)willsitbetweentheteeth(lightblue).Aspringclamp(yellow)isaddedtothecenterofthebandtohelpkeep thebandinplace Upinchers(green)willproduceaninwardforce(orangearrows)onthebutterflybandtohelpthe bandsitflushagainsttheteeth

TheButterfly+UPinchersDesignissimilartotheButterflyDesigninitsshape,size,and thicknessbuthasincorporatedaspringclampandUPincherstofixsomeflawsofthedesign.TheU Pinchersserveamainpurposeofcreatinganinwardforcethatpullsthematrixbandsclosetotheteethto maximizesurfacecontact.Inaddition,theycouldalsobeusedassomethingtoholdontowhilethedentist isplacingthematrixbandsinthepatient’smouth.Thedesignalsoincorporatesaninnovativespring clamptoholdthematrixbandsinplaceandwidenthegapbetweenthetargetedteethduringafilling Liketheothertwodesigns,thisdesignwouldbecreatedoutofadeadsoftmetal,wouldmostlikelybe singleuse,andwouldhaveacenterthicknessof0.0254mm.Alldimensionsofthebutterflybandinthis designwouldbethesameasintheButterflyDesign Withtheinclusionofallofthesecomponents,the devicewillbethemostexpensiveandhardestfabricate.

Figure8:Butterfly+UPinchersDesignSolidworks3DModel.Similartothebutterflydesign,thedevice consistsoftwosectionalmatrixbandswiththeadditionofUPinchers.Holesaddedtoaidintheremovalofthe device Notshowninfigure:springclamp

Figure9:Butterfly+UPinchersDesigninstalled.Thishanddrawnimageshowshowthebutterflyband(dark

IV. PreliminaryDesignEvaluation

A.DesignMatrix

**Thesixdesigncriteriaonthefar-mostleftcolumnwereevaluatedforeachpreliminarydesign Thedesignswere givenanumberscoreoutof5foreachcategoryandratingsweretotalledtodeterminewhichdesignwasbest (describedunderjustificationofcriteriasectionbelow) Shadedsectionsindicatethehighestrankingdesignforeach criteria Thelightershadingindicatestiesbetweendesigns

*Thefunctionalitycriteriawasbasedonthedesign’sabilitytoallowthedentisttocompletetheprocedurewithboth qualityandtimeefficiency

B.JustificationofCriteria

Functionality: Thefunctionalitycriteriawasbasedonthedesign’sabilitytoallowthedentisttocomplete theprocedurewithbothqualityandtimeefficiency.TheButterflyDesignreceivedthelowestscoreinthis category(2/5)duetoitslackofadjustabilityandtightness Thebandneedstosecurelyfitaroundthetooth inorderforaqualitytoothcontact,however,withtheButterflyDesign,somevariationintoothsizes amongstdifferentpatientswouldresultindifferentresults.Forexample,thegreaterthicknessinthe middleofthebandmayneedtobelongerforsomepatientsthanothers TheButterfly+UPinchers Designreceivedthehighestscoreinthiscategory(5/5).Thisdesignhaspincherswhichmaintainaclose fitbetweentheteethandmatrixacrosstheentiresection.Thisinwardforceallowsthedesigntobeused

Table 1: Preliminary Design Matrix

acrossvaryingshapesandsizesofteeth.Thespringclampalsoimprovesthedesignbywideningthegap betweentheteethifneeded.TheHandcuffDesignreceivedascoreof3/5becauseitmayhavefactorsthat contributetoincreasedproceduraltime Itisacircumferentialdesign,ratherthanasectionalone,that wouldrequiresteadyplacementofthebandinitsslotfillings.Thismaybebothafrustratingandtime consumingtask

Ease of Use: Thisdesigncriteriaoutlinedhoweasythedentalmatrixbanddesignwouldbefordentiststo placeinbetweenteethandremovefromthemouth Italsotookintoconsiderationanyviewobstruction thedentistwouldencounterfromtheshapeofthedesign TheHandcuffDesignscoredthelowest(2/5)in thisareaduetoitrequiringatediousplacementprocedureandthereforetediousremoval.Boththe ButterflyandButterfly+UPinchersdesignstiedforthehigherscoresof(4/5) Neitherdesignreceiveda perfectratingduetotheButterflyDesign’sslightlymoretimeconsumingplacementandtheButterfly+U PinchersDesign’spossibleviewobstruction.

Fabrication: Thiscriteriawasgradedonhoweasilythedesigncouldbefabricatedbasedontheintricacy ofpartsaswellascharacteristicsandavailabilityofmaterials Whileitisimportanttoensurethatthe designisviabletoactuallymanufacture,anddosoonascalethatwouldallowforthedevicetobe single-use,thefunctiondoesnotrequireintricacyandthereissignificantliteratureavailableonviable materials Therefore,thissectionwasgivenarelativelylowweightof15/100 TheHandcuffDesign scoredthehighestonthiscriteria(4/5)asitonlyrequiressimplemodificationstothematrixbands currentlyused,andthesame,singlematerial.BoththeButterflyandButterfly+UPinchersdesigns scoredlowerat(3/5)becauseofthethin,split,andcurvedmetalstructuresthatmustbecustom manufacturedandaccurateonaverysmallscale.

Ease of Sterilization: Allofthedesignshavethesamescoreforsterilization Thisisduetothefactthatall aremadefromthesamematerialandallwouldreactthesametosterilizationprocesses.Whilealldesigns aremeanttobeonetimeuse,theycouldbesterilizedbasedonthematerialusedanddurabilityofthe material

Safety: Eachdesignrankedverysimilarlyinsafetyasalldesignshavelittlechanceofharmingthepatient duringafillingprocedure.Alsoanymaterialsthatcouldbetoxictoapatientcouldbesubbedouteasilyin alldesigns.However,thehandcuffdesignrankedslightlyworseinsafetyduetoahigherchanceofthe bandslippingofforcomingundone

Cost: Thecostcriteriawasscoredbasedontype,andamountofmaterialrequired,andassociated fabricationcosts Thissectionwasgivenaweightof10/100astherelikelywon'tbemuchvariabilityand earlycostestimatesarenotaprimaryconcern.TheHandcuffDesignrankedhighestinthissection(4/5) asitisamodificationofthemostcommoncurrentmatrixbandswhichareinexpensive TheButterfly Designwasgivena3/5asthefabricationprocessismoreinvolved TheButterfly+UPinchersDesign wasgivena2/5asboththefabricationprocessismoredifficultandmorematerialisrequired.

C.ProposedFinalDesign

Theteamweightedandscoredeachcriteriaofthedesignmatrixwhiletakingtheclient’s preferenceforsectionalmatrixbandsovercircumferentialmatrixbandsintoconsideration This determinedthehighestscoringdesignideatobetheButterfly+UPinchersDesign.Thedesignwillbe hardertofabricateandwillcostmoreintermsofmaterialsandfabrication,buttheteambelievesthat thesehurdleswillbeworththefinalresult

V. FabricationPlan

A.Materials

Thecurrentindustrystandardformatrixbandsisadead-softsteelprimarilyduetoitsmechanical propertiesandnon-toxicity[5].“Dead-soft”steelreferstoalowercarbonandmanganesecontentatless than01%and02-05%,respectively[25] Additionally,itisprocessedbyheatingtoacritical temperatureandcooledmoreslowly,creatinglargergrains,makingthemateriallesshard,butmore ductile Thetensilestrengthis260-340MPa,whichmustberelativelyhightowithstandtightening aroundthetooth[26] TheRockwellBhardnessisabout55,whichisimportantforpreventing deformationsfromformingwhenpressedupagainsttheteethbutislimitedduetothemethodof processingwhichallowsforalowerelasticmodulus Theelasticmodulusis200-215GPa,sufficientfor bothallowingthethinmaterialtobendaroundthetoothwhilemaintainingtightcontactwiththetooth evenwhenwithstandinghighoutwardstressesfrompackingthefillingmaterial[26].

Inthepast,materialssuchascopper,silverandtitaniumhavebeenusedtofabricatematrixbands butthemechanicalcharacteristics,biocompatibility,andcostofdead-softsteelhavemadethemobsolete [5]

B.Methods

OncetheCADmodeloftheproposedfinaldesignisfullyrefinedwithproperdimensionsand materials,itcanbesenttoaprofessional3rdpartymanufacturerofprecisionmetalparts.Moreresearch willbedonetofindamanufacturercapableoffabricatingpartsonthescaleofhundredthsofamillimeter, whichistheprecisionrequiredforthedesiredthicknessofourdesign Fromearlybrainstormingsessions, itispostulatedthatthiscouldbedonevialasercuttingthedesiredshapefromablockofdead-softsteel. Withthisfirstprototype,amoldcanbecastandfurthermanufacturingcanbedonewiththismold

C.Testing

Bothqualitativeandquantitativetestingwillbedoneonthefirstprototypetoensurecompliance withproductdesignspecificationsandFDAregulations.Primaryqualitativetestingwillbedonewiththe teamtoconfirmthatthematrixbandfitsintheinterproximalspaceofthemouthmodel,foundinthe expensestableofAppendixB.Thematrixbandwillalsobetestedtoensureitproperlyconformswiththe teethandiscompatiblewiththespringclamp Secondaryqualitativetestingwillbedonewiththeclient, Dr DonaldTipple,alongwithhiscolleaguestodetermineifthenewdesignismoreeasilyandquickly installedandremoved,withoutimpedingontheefficacyorspeedofthetoothrestoration.Quantitative

testingwillbedonebothvirtuallyinSolidWorksonourCADmodelwithproperdimensionsand materials,andphysicallywiththefirstprototypeinanMTSmachine.Thesetestsmustshowequivalentor superiortensileandductilepropertiestotheTofflemirebandsthatourclientcurrentlyuses

VI. Conclusion

Dentalcareisveryimportantforoverallwellbeing.One-thirdofadultshaveuntreateddental caries;ifleftuntreated,thesecanleadtoinfectionandpermanenttoothloss 175millionpeoplereceiveat leastonedentalfillingeveryyear[27].Providingdentistswiththepropertoolsandresourcestoperform thesefillingswithbothqualityandtimeefficiencyisessentialinhelpingthemillionsofpeoplewith untreatedcavities Thecurrentprocesstofillcavitiesvariesdependingontheclassificationandseverity ofthecavity.Matrixbandsareatoolusedbydentiststoassistinprovidingthepropercontourofthetooth duringfilling Theyareoftenusedalongwithtoothwedgeswhichservetotightenthesealandprevent gingivaloverhang ClassIIcavitiesarethoseontheinterproximalsurfaceofpremolarsandmolars They areknowntobedifficulttorestoreduetothenecessityofmaintainingaproperandtighttoothcontact [28] Currentmatrixbands,suchassectionalandTofflemirematrixbandshaveshortcomingswhenit comestorestoringClassIIcavitiesbecausetheycannotbeusedconcurrentlytofilltwoadjacentteeth. Thedentistmustperformonefilling,thenrepositionthematrixbandandwedgeinordertoperformthe secondfilling Thisisnotonlyverytedious,butalsoverytimeconsumingandminimizestheamountof timedentistshavetocareforotherpatients.

Theteamwastaskedwithdesigningadevicethatwouldallowconcurrentrestorationoftwo adjacentinterproximalcavities Wheninitiallyreviewingthisproblem,theteamdiscussedthedesignsof thepreviousteam.Oneofthedesigns,TheButterfly,stoodoutandseemedtoofferaneasysolutiontothe currentissueathand TheButterflyallowedthepropertoothcontacttoberestoredduetoitstwomatrix bandsconsistingofhalfthethicknessofaregularsectionalband However,theteamanticipatedsome issueswiththisdesignuponfurtherconsideration.Theplacementandremovalwouldbedifficultwithout anadditionaltooltoaidthedentists Theteamwasalsounsurewhetherthecontactofthebandwouldbe tightalongthesurfaceofthetoothwithoutanadditionalforcetokeepitinplace.Basedonthese considerations,theteamcameupwithtwoadditionaldesignstoevaluateinthedesignmatrix.The HandcuffDesigntookafullydifferentapproachbybeingacircumferentialmatrixbandthatreliesonits ownopeningstoanchorandtightenthebandaroundthetooth.TheButterfly+UPinchersDesign includespinchersthatimprovesomeoftheshortcomingsoftheButterflyDesign,butcomeswithitsown shortcomings(suchaspotentiallyobstructingtheviewofthedentist) Thesethreedesignswereevaluated inadesignmatrix,andultimately,TheButterfly+UPinchersDesignwasthewinner.Thisisduetothe inwardforcethepinchersexertonthematrixband,ensuringatightandpropertoothcontact,while allowingforeasyremovalandplacementwiththepinchers.Theteamwill,thus,bemovingforwardwith TheButterfly+UPinchersdesign.

Therearevariousconsiderationsthatmustbemadepriortofabricationofthisdesign Theteam mustperformsomesortofassessmenttodeterminewhetherthepincherswouldblocktheviewofthe dentist.Thiscanbedonebyquantitativeassessmentsoftheshapeofthedevicewithaprototypethatcan beusedonatoothmodel Additionally,theteamhasdiscussedincludingatabwithaholeforfurtherease ofplacementandremovalviatweezers.Currentsectionalmatrixbandshaveatabwithaholeonthe occlusaledgeandwingendsforthisexactpurpose Incorporatingatabmayfurtherincreasetheeaseof useofthisdesign

Theteamplansonproceedingwiththisdesignusingdead-softsteel.Oncetheteamhasfinalized theCADmodelofourproposedfinaldesignwithnecessarymodifications,theteamwillsenditouttoa thirdpartymanufacturer Qualitativeandquantitativetestingwouldthenbedonetoensureitmeetsthe productdesignspecifications.Qualitativetestingwouldincludetheteamutilizingthematrixbandina modelmouthfollowedbyDr DonaldTipple’sevaluation QuantitativetestingwillbedoneinSolidWorks andthenphysicallydoneinanMTSmachine Successfultestingresultswillrevealequivalentmechanical propertiesandeaseofusecomparedtocurrentmatrixbands,whileallowingfordecreasedprocedural timeduetotheconcurrentfillingsitwillallow

VII. References

[1]R.M.Benjamin,“OralHealth:Thesilentepidemic,”Publichealthreports(Washington,D.C.:1974), 2010.[Online].Available:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2821841/.[Accessed: 20-Oct-2021].

[2]“WhattoExpectwithDentalFillings.”DentistOfficeinCincinnati,OH, https://www.blueashdental.com/what-to-expect-with-dental-fillings.

[3]“IsaDentalFillingAlwaysRequiredforCavities?”DavidL.BakerDDSPAPlanoTexas,4June 2019,https://www.davidbakerdds.com/blog/is-a-dental-filling-always-required-for-cavities/.

[4]Lucas-Rincón,S.E.,Robles-Bermeo,N.L.,Lara-Carrillo,E.,Scougall-Vilchis,R.J.,Pontigo-Loyola, A.P.,Rueda-Ibarra,V.,Loyola-Rodríguez,J.P.,Escoffié-Ramirez,M.,&Medina-Solís,C.E.(2019). Interproximalcariesandprematuretoothlossinprimarydentitionasriskfactorsforlossofspaceinthe posteriorsector:Across-sectionalstudy.Medicine,98(11),e14875. https://doiorg/101097/MD0000000000014875

[5]“AhistoricalreviewofdentalmatricesfromMDJ,” Scribd [Online] Available: https://wwwscribdcom/document/112847146/A-Historical-Review-of-Dental-Matrices-From-MDJ [Accessed:20-Oct-2021]

[6]Durr-E-Sadaf,AhmadMZ,GaikwadRN,ArjumandB Comparisonoftwodifferentmatrixband systemsinrestoringtwosurfacecavitiesinposteriorteethdonebyseniorundergraduatestudentsat QassimUniversity,SaudiArabia:Arandomizedcontrolledclinicaltrial IndianJDentRes 2018 Jul-Aug;29(4):459-464 doi:104103/ijdrIJDR 26 17 PMID:30127197

[7]ShaalanO.O.(2020).EvaluationofMatrixBandSystemsforPosteriorProximalRestorationsamong EgyptianDentists:ACross-SectionalSurvey ActastomatologicaCroatica,54(4),392–400 https://doiorg/1015644/asc54/4/6

[8] Matrix placement for Class II Amalgam Restoration.[Online].Available: http://www.columbia.edu/itc/hs/dental/operative/matrixband.html.[Accessed:20-Oct-2021].

[9]“Pro-matrix|disposablematrixsystem,”Pro-Matrixbanddisposablematrixsystem.[Online]. Available:https://www.astekinnovations.co.uk/promatrix.php.[Accessed:20-Oct-2021].

[10]“MedicosPro-MatrixSingle-UseMatrixBand,”YouTube.DentalProductShopper,21-Jun-2017.

[11]TriodentV3Betteroutcomesstarthere,”TriodentV3|DentsplySirona.[Online].Available: https://www.dentsplysirona.com/en-au/categories/restorative/triodent-v3.html.[Accessed:23-Sep-2021].

[12]“DentsplySironaLaunchesDsPrimetaper,AnnouncesCOMPREHENSIVERestageofITSImplant Business,”DentalProductsReport,23-Sep-2021 [Online] Available: https://wwwdentalproductsreportcom/view/dentsply-sirona-launches-ds-primetaper-announces-comprehe nsive-restage-of-its-implant-business [Accessed:23-Sep-2021]

[13]A E G I S Communications,“V3sectionalmatrixsystem-triodent:Insidedentistry,”Triodent| Volume5,Issue10|InsideDentistry [Online] Available:

https://www.aegisdentalnetwork.com/id/2009/12/v3-sectional-matrix-system-triodent.[Accessed: 23-Sep-2021].

[14]“DentalMatrixSystems,”Dentalcompare [Online] Available: https://wwwdentalcomparecom/Restorative-Dentistry/4630-Dental-Matrices/

[15]R SCHEIDandG WEISS,Woelfel'sdentalanatomy BURLINGTON,MA:JONES& BARTLETTLEARNING,2020

[16]U F O Themes,“Principlesoftoothpreparation,”PocketDentistry,12-Feb-2015 [Online] Available:https://pocketdentistrycom/principles-of-tooth-preparation-2/

[17]M Ahmad,“AHistoricalReviewofDentalMatrices,”MalaysianDentalJournal,vol 33,no 2,pp 1–7,2011

[18]“Dentalfillings:Gold,Amalgam,Composite,ceramicandmore,”WebMD [Online] Available: https://wwwwebmdcom/oral-health/guide/dental-health-fillings [Accessed:23-Sep-2021]

[19]“JRRandTofflemire,”Net32 [Online] Available: https://www.net32.com/search?q=JR%2BRand%2BTofflemire%2Btype.[Accessed:22-Sep-2021].

[20]Bell,Eddie.“UnderstandingMetalHardness.”RioGrande,29Oct.2020, www.riogrande.com/article?name=UnderstandingMetalHardness.

[21]K.Watson,“Hardestsubstanceinthehumanbody:Allabouttoothenamel,”Healthline, 22-Sep-2020.[Online].Available:

https://www.healthline.com/health/hardest-substance-in-the-human-body#:~:text=According%20to%20th e%20Mohs%20Hardness,10%20on%20the%20Mohs%20scale.[Accessed:23-Sep-2021].

[22]S.Baliga,S.Muglikar,andR.Kale,“Salivaryph:Adiagnosticbiomarker,”JournalofIndianSociety ofPeriodontology,vol.17,no.4,p.461,2013.

[23]Lowe,A.,Burke,F.,McHugh,S.etal.Asurveyoftheuseofmatrixbandsandtheir decontaminationingeneraldentalpractice.BrDentJ192,40–42(2002). https://doi.org/10.1038/sj.bdj.4801286

[24]“CFR-codeoffederalRegulationsTitle21,” accessdata.fda.gov.[Online].Available: https://wwwaccessdatafdagov/scripts/cdrh/cfdocs/cfcfr/CFRSearchcfm?fr=8724565 [Accessed: 23-Sep-2021]

[25]Flyingchimp,“Deadsoftsteel,” Falcon Aerospace,01-Aug-2013.[Online].Available: https://www.falconaerospace.com/dead-soft-steel/.[Accessed:20-Oct-2021].

[26]“ASTMA109Gradeno.5dead-soft,” Matmatch.[Online].Available: https://matmatch.com/materials/minfm65939-astm-a109-grade-no-5-dead-soft.[Accessed:20-Oct-2021].

[27]R.S.King,“ACloserLookatTeethMayMeanMoreFillings,”TheNewYorkTimes,28-Nov-2011. [Online].Available:

https://www.nytimes.com/2011/11/29/health/a-closer-look-at-teeth-may-mean-more-fillings-by-dentists.ht ml.[Accessed:19-Oct-2021].

[28]Admin,“Surveyresultsshowwhatiskey:ClassIIfillings-routinebutstillchallenging,”Press &Media,07-Aug-2017.[Online].Available: https://newsdentsplysironacom/en/business-units/restorative/2017/class-ii-fillings--routine-but-still-chall enginghtml [Accessed:19-Oct-2021]

VIII. Appendix

A.AppendixA-ProductDesignSpecifications

ApproximatingSurfaceMatrixBand

Product Design Specifications

October20th,2021

Client: Dr.DonaldTipple

Advisor: Dr.TracyPuccinelli(Section309)

Team: TaraBoroumand(TeamLeader) tboroumand@wisc.edu

GraceJohnson(Communicator) gkjohnson4@wisc.edu

MatthewFang(BSAC) mjfang@wisc.edu

DraesonMarcoux(BWIG) dmarcoux@wisc.edu

TrevorSilber(BPAG) tjsilber@wisc.edu

Function:

Matrixbandsareacommonlyuseddentaltoolwhichassistdentistsbycreatinganoutside contourofadecayedtooth.Thiscontourmaintainsthetooth’sstructureandshapeduring restorativeprocedures,suchascavityfillings.Duringtypicalfillingproceduresforcavitieson interproximalsurfaces,dentistsmustfilleachtoothseparately Thistediousprocedureisdueto matrixbandsnotfittingadjacenttooneanotherintheinterproximalspace,asthethicknessof twobandsexceedsthetoothcontactdiameterbetweentheteeth.Theresultingprocessofplacing matrixbandsforbothteethiscumbersomeandtimeinefficient.Anewdentalmatrixbanddesign isdesiredtoalleviatetheneedtorepeatedlyplacebands.Thedeviceshouldemployadual-band systemwithathicknesslessthanorequivalenttocurrentmatrixbands,0.05mm,throughout suchthatthefitissecureandthebandmoldstotheappropriateconvex/concavecontourofeach tooth.Thefinalizedproductshouldalsomaintainthetensilestrength,about400MPa, malleability,andspaceefficiencyofcurrentmatrixbands.Thematerialusedtofabricatethe matrixbandmustnotcauseanyirritation,mustbebiocompatible,andmustbenon-reactiveto fillingmaterials.

ClientRequirements:

● Thematrixbandshouldbesectional,ornon-circumferential,sothatonlythe approximatingsurfacesoftheteethbeingfilledareincontactwithit.

● Nickelandotherirritatingmaterialsmustnotbeusedtomakethematrixband.

● Thematerialusedtofabricatethematrixbandshouldnotinteractwithoradhereto materialsusedinfillingcavitiesandmustbebiocompatible.

● Thedevicemusteitherbesingle-useorsterilizableifusedmorethanonce.

● Thematrixbandshouldincludeasmallholeforflosstofitthroughsothatdentistsmay easilyretrievethepieceifitfallsintoapatient’smouth.

● Theinferioredge,orthegumedge,ofthematrixbandshouldbemadeslightlyconvexto encapsulatetheentirecavitybeingfilledandtohelpwithorientationofthedevice.

DesignRequirements:

1. PhysicalandOperationalCharacteristics

a. Performance Requirements:

i. Thematrixbandshouldbeabletomaintainitsstructureandfunctionfrom thetimeitisplacedinthemouthuntilthefillingprocedureisover,upto1 hour[1].

1. Thedevicewillmostlikelybesingle-use,butifsterilizable,it shouldbecapableofperformingupto50procedures.

ii. Thedeviceshouldmaintainsimilarmechanicalcharacteristicsofexisting matrixbands,withstandingloadsplacedonitduringfilling.

1. Itshouldstillbemalleableandabletoshapearoundanytooth.

a. Tensilestrengthofdead-softsteelis260-340MPaandthe elasticmodulusis200-215GPa[2].

iii. Thedeviceshouldincorporatewedgesoranothercomponentthat effectivelyseparatestheapproximatingteethbeingfilled.

b. Safety:

i. Thematerialusedtofabricatethematrixbandshouldnotcauseany irritationtopatients(i.e.Nickel)andmustbebiocompatible.

ii. Thedevicemustnothaveanysharpedgesorpoints.

iii. Thedevicemustcomewithasafetylabeltoinformusershowtoproperly handleittoensuresafety

1. Itmustalsocomewithasafetywarningthatencouragesusersto disposeofthedeviceifsterilepackagingistamperedorthedevice isbroken.

c. Accuracy and Reliability:

i. Thedevicethicknessshouldbeaccuratetoahundredthofamillimeter duringmanufacturetoensureitremainsbelow0.05mm,anacceptable interproximalspace[3].

ii. Thematrixmustmaintainthisthicknessanditsconformationtothetooth suchthattherearenoabnormalitieswhenthefillingispackedand solidified.

d. Life in Service:

i. Thedevicemustmaintainthetargetpropertiesforthedurationofthe procedureinwhichitisused.Foracavityfilling,thisisgenerallywithin anhour[1].Currently,mostmatrixbandsaresingle-usetoensuresterile conditions.

e. Shelf Life:

i. Mostcurrentmatrixbandsaremadeofstainlesssteelornaturalplastics whichhaveanindefiniteshelflifeforpracticalpurposes.Ourdevice shouldmatchthisshelflifewhilekeptintheproperpackaging.

ii. Thisdeviceshouldbekeptatornearroomtemperature.

f. Operating Environment:

i. Thehumanmouthisavariableenvironmentwithbothphysical,chemical andbiologicalfactorstoconsider

1. Thisdevicemustmaintainitsintegritywhenforcedinbetween teethwhichhaveaMohshardnessratingof5[4].Itmustalsobe bluntenoughtopreventinjuryofthe,potentiallycompromised, toothandsurroundinggums.Operatingtemperaturerangesfrom roomtemperature(~20℃)tobodytemperature(~37℃).

2. ThemouthhasapHwitharangeof6.2-7.6.Therearealsoa varietyofenzymesinthesalivathatthedevicemustwithstand[5].

3. Thedevicemustbenon-toxictothecellsofthebodyaswellas essentialbacteriaofthemouthandfreeofcommonallergenslike nickel.

g. Ergonomics:

i. Thenewdeviceshouldbeeasierandmuchlesstimeconsumingtoinstall, adjust,andusethanexistingproductsonthemarket,likethesectionaland circumferentialmatrixbands.

h. Size:

i. Thedeviceshouldbeadjustableand/orscalabletoaccommodateallsizes ofteeth.Thedimensionsofhumanteethcanvarygreatlywithtypeof tooth,sex,age,race,andmanyotherfactors.Onaverage,maxillaryteeth haveacrownheightof8.77mm,rangingfrom7.2mmto11.2mm,and

mandibularteethhaveacrownheightof8.62mm,rangingfrom7.5mm to11.0mm[6].

ii. Theperimeterofteethcanbeapproximatedbytreatingteethasrectangles andusingaveragemesiodistaldiameterandfaciolingualdiameter measurementsof8.20mmand8.71mm,respectively.Thisapproximation wouldresultinanaveragetoothperimeterof33.82mm,witharangeof 22mmto45.8mm[6].

iii. Currentmatrixbandscommonlycomeinthreedifferentthicknesses:0.001 gauge(0.0254mm),0.0015gauge(0.0381mm),and0.002gauge(0.0508 mm)[7].Thedeviceshouldhaveasimilarorsmallerthicknessthan currentmatrixbands.

i. Weight:

i. Currentmatrixbandsaremadeofstainlesssteel.Usingthegaugesize (0.0015),approximatetoothsize(height=8.695mm,perimeter=33.83 mm),andthedensityofstainlesssteel(7.99g/cm^3)wecancalculatethe weightofonematrixband[8].Thiscomesouttoaweightof0.0895 grams.Thedeviceshouldweighsimilartocurrentmatrixbands.

j. Materials:

i. Thematrixbandisexpectedtobemadeoutofadeadsoftmetal,meaning itisrigidinitsrestingstatewhilestillbeingmalleable [9].Thiswould includematerialssuchasstainlesssteelandaluminum.Thematerialmust alsobenon-toxictohumanstopreventharmtoapatient.Thematerialalso mustnotreactwithbothsilverfillingsandwhitefillings.

ii. Ifpossible,thematerialshouldbeabletobesanitized.Thiswouldallow foramoresustainableproductthatisalsomorecosteffective.

iii. Thewedgeistraditionallymadeoutofwood.Forthepurposesofthis project,thewedgewilllikelybemadeofsomesortofplasticduetothe easeoffabrication.

k.

Aesthetics, Appearance, and Finish:

i. Thebandandthewedgeshouldnotbecoloredthesameasatoothto avoidconfusionwhileoperating.Theaestheticswerenotaprioritywith theclientanddependmoreonfunctionality.

2. ProductionCharacteristics

a. Quantity:

i. Theproductisexpectedtobenon-reusable.Thatmeansifitismade marketavailable,theproductwouldneedtobemassproducedtomeetthe

demandofdentistsforeveryadjacenttoothfillingprocedure.Ifthefinal designwereabletobesterilized,thenthedemandfortheproductwould godowntooneperdentist.Forthepurposesoftheproduct,therewill likelybe1-3prototypesproduced.

b. Target Product Cost:

i. Thegoalwhenplanningoutthedesignsistokeeptheproductsascost effectiveaspossiblewithoutsacrificingquality.Currentmatrixbandsgo forabout50centstoadollar[10].Giventhepossiblecomplexityofour design,itmightbemoreexpensivetofabricatebutkeepingthepriceunder $3-5shouldbeprioritized.

ii. Thebudgetfortheprojectisexpectedtobearound$200-300giventhe testingneededtobedone.

3. Miscellaneous

a. Standards and Specifications:

i. FDAapprovalisnecessaryformedicaldevices.Currentmatrixbandsare Class1devicesasspecifiedintheCodesofRegulationsTitle21,Chapter 1,SubchapterH,Part872SubpartE.Theyareidentifiedaslowrisk devicesthatpresentminimalpotentialforharm.Ifthenewdesignutilizes thesamematerialsusedbefore1976,itwouldbeexemptfrompremarket notificationproceduresspecifiedinSubpartE[11].Otherwise,a premarketnotificationsubmissionwouldneedtobecompletedtotheFood andDrugAdministrationatleast90dayspriortotheproposed introductionoftheproduct[11].AnInvestigationalDeviceExemption (IDE)wouldneedtobeobtainedtopursueclinicalstudieswiththedevice tocollectdataonsafetyandeffectivenessinsupportofthePremarket Approval(PMA)applicationorPremarketNotification510(k)submission. ThesestudiesmustbeapprovedbytheInstitutionalReviewBoard(IRB) beforethestudiesbegin[12].

b. Customer:

i. Thisdesignshouldmainlyappealtodentists.Thus,thedesignneedstobe optimizedtofittheuser’scomfortandeaseofusewhiledecreasing proceduraltime.Dentalsupplierswouldalsobetargetcustomers,sothe designmustoutcompeteothersonthemarket.Theclientspecifications shouldbecloselyfollowed,astheclienthastheperspectiveofadentist and,thus,potentialcustomer.

c. Patient Related Concerns:

i. Thedevicewillbeindirectcontactwiththepatient’soralcavity,sothe materialsmustbenon-toxicandnon-allergenic.Commonmetalallergies include:nickel,cobalt,copperandchromium[13].Thisdesignshouldalso beone-timeuse,similartothecurrentmatrixbandused.Thus, sterilizationwouldnotbeaconcern.Ideally,thedevicewouldnotaddany additionaldiscomfortduringthefillingprocess.

d. Competition:

i. Therearenumerousdevicesandtechniquesthatcanbeconsidered competingdesigns,however,thosethatrelatemosttothisprojectare sectionalmatrixsystems.TheTriodentV3Ringusedalongsidethe TriodentWave-Wedgeisadvertisedasasectionalmatrixsystemthat allowsforsuperiorfunctionalitycomparedtothecircumferentialband (tofflemire)[14][15][16].SpecificallyinClassIIcavities,ifthisTriodent ringisusedtoseparateadjacentteethwiththeplacementoftwomatrix bands,thecontactbetweentheteethwouldnotofferoptimalcontact leadingtoalargergapthandesired.

References

[1]“Dentalfillings:Gold,Amalgam,Composite,ceramicandmore,”WebMD.[Online].

Available:https://www.webmd.com/oral-health/guide/dental-health-fillings.[Accessed: 23-Sep-2021].

[2]“ASTMA109Gradeno.5dead-soft,” Matmatch.[Online].Available: https://matmatch.com/materials/minfm65939-astm-a109-grade-no-5-dead-soft.[Accessed: 20-Oct-2021].

[3]U.F.O.Themes,“Principlesoftoothpreparation,”PocketDentistry,12-Feb-2015.[Online].

Available:https://pocketdentistry.com/principles-of-tooth-preparation-2/.[Accessed: 23-Sep-2021].

[4]K.Watson,“Hardestsubstanceinthehumanbody:Allabouttoothenamel,”Healthline, 22-Sep-2020.[Online].Available:

https://www.healthline.com/health/hardest-substance-in-the-human-body#:~:text=According%20 to%20the%20Mohs%20Hardness,10%20on%20the%20Mohs%20scale.[Accessed: 23-Sep-2021].

[5]S.Baliga,S.Muglikar,andR.Kale,“Salivaryph:Adiagnosticbiomarker,”JournalofIndian SocietyofPeriodontology,vol.17,no.4,p.461,2013.

[6]R.I.C.K.N.E.C.SCHEIDandG.A.B.R.I.E.L.A.WEISS,Woelfel'sdentalanatomy. BURLINGTON,MA:JONES&BARTLETTLEARNING,2020.

[7]“JRRandTofflemire,”Net32.[Online].Available: https://www.net32.com/search?q=JR%2BRand%2BTofflemire%2Btype.[Accessed: 22-Sep-2021].

[8]“305stainlesssteelalloydatasheet,”CombinedMetalsofChicago,14-May-2018.[Online]. Available:https://www.combmet.com/305-stainless-steel-alloy/.[Accessed:22-Sep-2021].

[9]Bell,Eddie.“UnderstandingMetalHardness.”RioGrande,29Oct.2020, www.riogrande.com/article?name=UnderstandingMetalHardness

[10]Lowe,A.,Burke,F.,McHugh,S.etal.Asurveyoftheuseofmatrixbandsandtheir decontaminationingeneraldentalpractice.BrDentJ192,40–42(2002). https://doi.org/10.1038/sj.bdj.4801286

[11]“CFR-codeoffederalRegulationsTitle21,”accessdata.fda.gov.[Online].Available:

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=872.4565. [Accessed:23-Sep-2021].

[12]CenterforDevicesandRadiologicalHealth,“Overviewofdeviceregulation,”U.S.Food andDrugAdministration.[Online].Available:

https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance/overvi ew-device-regulation.[Accessed:23-Sep-2021].

[13]Y.YoshihisaandT.Shimizu,“Metalallergyandsystemiccontactdermatitis:Anoverview,” Dermatologyresearchandpractice,2012.[Online].Available: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3369403/.[Accessed:23-Sep-2021].

[14]“TriodentV3Betteroutcomesstarthere,”TriodentV3|DentsplySirona.[Online].

Available:https://www.dentsplysirona.com/en-au/categories/restorative/triodent-v3.html. [Accessed:23-Sep-2021].

[15]“DentsplySironaLaunchesDsPrimetaper,AnnouncesCOMPREHENSIVERestageofITS ImplantBusiness,”DentalProductsReport,23-Sep-2021.[Online].Available: https://www.dentalproductsreport.com/view/dentsply-sirona-launches-ds-primetaper-announcescomprehensive-restage-of-its-implant-business.[Accessed:23-Sep-2021].

[16]A.E.G.I.S.Communications,“V3sectionalmatrixsystem-triodent:Insidedentistry,” Triodent|Volume5,Issue10|InsideDentistry.[Online].Available: https://www.aegisdentalnetwork.com/id/2009/12/v3-sectional-matrix-system-triodent. [Accessed:23-Sep-2021].

B.AppendixB-ExpensesTable