MECHANICS OF THE TAPER INTEGRATED SCREWED-IN (TIS) ABUTMENTS USED DENTAL IMPLANTS

Transcription

1 MECHANICS O HE APER INEGRAED SCREWED-IN (IS) ABUMENS USED DENA IMPANS by Dinçe Bozkaya, Gaduate Student Sinan Müftü 1, Ph.D. Aociate Pofeo Notheaten Univeity Depatment of Mechanical Engineeing Boton MA Octobe Coeponding autho: Notheaten Univeity Depatment of Mechanical Engineeing, 334 SN Boton, MA el: , ax: muftu@coe.neu.edu 1

2 ABSRAC he tapeed implant-abutment inteface i becoming moe popula due to the mechanical eliability of etention it povide. Conequently, undetanding the mechanical popetie of the tapeed inteface with o without a cew at the bottom ha been the ubject of a conideable amount of tudie involving expeiment and finite element (E) analyi. hi pape focue on the tapeed implant-abutment inteface with a cew integated at the bottom of the abutment. he tightening and looening toque ae the main facto in detemining the eliability and the tability of the attachment. Analytical fomula ae developed to pedict tightening and looening toque value by combining the equation elated to the tapeed inteface with cew mechanic equation. hi enable the identification of the effect of the paamete uch a fiction, geometic popetie of the cew, the tape angle, and the elatic popetie of the mateial on the mechanic of the ytem. In paticula, a elation between the tightening toque and the cew petenion i identified. It wa hown that the looening toque i malle than the tightening toque fo typical value of the paamete. Mot of the tightening load i caied by the tapeed ection of the abutment, and in cetain combination of the paamete the petenion in the cew may become zeo. he analytical method developed hee wa applied to a 4.8 mm II implant-abutment ytem. he calculation pefomed to detemine the looening toque a a pecentage of tightening toque eulted in the ange %, depending on the value of tape angle and the fiction coefficient. Keywod: Dental implant; ape lock; Moe tape; Conical intefeence fit; apeed intefeence fit; Connection mechanim; ooening toque, ightening toque 2

3 INRODUCION he eliability and the tability of an implant-abutment connection mechanim i an eential peequiite fo long-tem ucce of dental implant. 1 High ate of cew complication uch a cew looening ha been encounteed with the cew-type implant-abutment connection mechanim. 2,3 Inadequate peload, the mifit of the mating component and otational chaacteitic of the cew wee conideed to be the eaon leading to cew looening o factue. 3 apeed implant-abutment attachment with o without cew peent an altenative method to the cew type attachment ytem. In thi pape, the tem tape integated cewed-in (IS) abutment i ued to indicate an abutment which ue imultaneouly a cew and a tapeed fit, wheea an abutment which ue only the tapeed intefeence fit a the connection mean i called a tapeed intefeence fit (I) abutment. ou commecial implant ytem ae hown in ig 1. he deign by Nobel Biocae (Nobel Biocae AB, Götebog, Sweden) ue a cew, the deign by Ankylo (Degua Dental, Hanau-Wolfgang, Gemany) and II (Intitut Staumann AG, Waldenbug, Switzeland) ue IS type abutment; and the deign by Bicon (Bicon Inc., Boton, MA, USA) ue the I type abutment. he main advantage of the IS abutment i educing cew-looening incident, attibuted to the inceaed intefacial tength between implant and abutment. A high incidence of cew looening, up to 40%, wa found fo ytem uing cew-only implant-abutment connection, wheea the failue ate fo tapeed inteface implant wa lowe, a much a 3.6% to 5.3%. 4 A etopective tudy with 80 implant howed that uing the IS connection povide a vey low incidence of failue. 5 he lack of etievability could be conideed a the diadvantage of the ytem. 6 Clinical tudie 3

4 howing the ucce of the IS type implant-abutment inteface encouaged the eeache and implant companie to focu on undetanding and evaluating the mechanical popetie of the tapeed inteface. An expeimental tudy by Noton 7 invetigated the vaiation of the looening toque a a pecentage of tightening toque with epect to diffeent paamete uch a tightening toque ( N.mm), tape angle (8 o and 11 o ), intefacial uface aea (15.3 and 27.9 mm 2 ), exitence of aliva contamination and time delay to looening (10 and 60 minute). Stong coelation wa found between looening toque a the pecentage of tightening toque. he tape angle, aliva contamination and time delay to looening did not have a ignificant effect on the looening toque, wheea the intefacial uface aea eemed to have a pofound effect on the efficiency of the connection. he efficiency i defined a the atio of the looening toque to the tightening toque. At clinically elevant toque level ( N.mm), the looening toque wa 84%-91% of the tightening toque. hi finding wa in contat to the expeimental wok done by Sutte et al. 8, who howed the looening toque to be 10-15% highe than the tightening toque. It wa alo hown that dynamic loading eulted in 50% eduction of the looening toque; howeve, no deceae occued in cone-cew connection afte 1 million cycle. 8 he 8 o tape angle with 2 mm diamete cew at the bottom wa elected to be the optimum deign that povide a ecue aembly between implant and abutment. Squie et al. 6 invetigated the effect of anodization and eduction of uface aea on the tightening and looening toque. A 31% eduction of uface aea did not caue a ignificant change in the looening toque howeve the uface coating caued a 20% deceae in the looening 4

5 toque. In thei tudy, fo 350 N.mm tightening toque, the looening toque wa in the ange of % of the tightening toque. he tength of the tapeed inteface in a IS abutment wa aeed by expeimental and finite element method. he tapeed inteface wa found to be favoable in tem of eitance to bending foce. 9 he tee induced by off-axi load wee compaed fo tapeed and butt-joint connection. It wa concluded that the tapeed inteface ditibuted the tee moe evenly when compaed to the butt joint connection. 4 In an in-vito compaative tudy of two commecially available implant ytem, the conical implant-abutment connection, added to the ytem, inceaed the eitance of the implant ubjected to conideable amount of foce and bending moment. 9 Alo, the conical inteface allowed a lage maximum tightening toque. he maximum tightening toque wa 4000 N.mm fo the IS abutment, which wa conideably geate than the 1250 N.mm of the cew-only connection. 8 Bacteial leakage though implant-abutment inteface i anothe ignificant facto affecting the long-tem tability of the implant. 11 Although the tapeed inteface i conideed to be acting a a eal againt bacteial leakage and colonization, it cannot completely pevent leakage due to the gap caued by the mifit between the component. he ate of bacteial leakage diminihe a the degee of mifit deceae and the tightening toque of the cew inceae. 10,11 he mechanic of the puely I type implant wa fit explained by O Callaghan et al. 13 and then by Bozkaya and Müftü. 14,15 Appoximate analytical olution fo the contact peue, the pull-out foce and looening toque acting in a tapeed intefeence wee developed by modeling the tapeed intefeence a a eie of 5

6 cylindical intefeence with vaiable adii. hee fomula wee veified by non-linea finite element analye fo diffeent deign paamete. 14 In thi pape, appoximate cloed-fom fomula ae developed fo etimating the tightening and looening toque magnitude fo the IS type abutment connection. he cloed fom equation fo the tapeed intefeence fit 14 ae combined with cew mechanic equation to detemine the looening and tightening toque a a function of vaiou deign paamete. he efficiency of the ytem, defined a the atio of the looening toque to the tightening toque, i invetigated. MAERIAS AND MEHODS A tape integated cewed-in (IS) abutment i placed into the implant by applying a tightening toque. he tightening poce caue intefeence in the tapeed pat and alo advance the cew whee the thead of the abutment and implant engage with a poitive foce. hi eult in a tenile load in the cew known a the peload. he geometic paamete that affect the mechanic of the connection ae defined in igue 2 whee the implant i depicted a a cylinde. he balance of foce and toque acting on thi ytem duing tightening ae evaluated uing the fee body diagam given in igue 3 and igue 4. Duing tightening, the cew peload will be elated to the eultant nomal foce N, acting on the tapeed ection due to the intefeence fit. hu by uing, the well known, powe cew elation 16 and the tapeed intefeence fit equation given by Bozkaya and Müftü 14 it i poible to develop cloed fom elation fo the tightening and looening of IS type abutment. 6

7 he eultant nomal foce N due to intefeence fit in the tapeed ection of the abutment, hown in igue 3a, i given a 14, πe zin2θ N = 3 b in 3 + in 6b c ( 2 ab) c θ( ab c θ) (1) whee c i the contact length, b 2 i the oute adiu of the implant, ab i the bottom adiu of the abutment, θ i the tape angle a hown in igue 2, z i the axial diplacement of the abutment duing tightening, and, E i the elatic modulu of implant and abutment, aumed to be made of the ame mateial. he Scew Peload When a IS type abutment i cewed into the implant, a tenile peload, develop in the cew and a eiting foce along the main axi of the abutment develop in the tapeed pat. hi eiting foce and the cew peload ae equal in magnitude. he eiting foce ha contibution due to fiction foce µn and the nomal foce N, and it can be found fom the fee body diagam in igue 3a. Note that the fiction foce develop along a helical path, a hown igue 3d, whoe helix angle i equal to the lead angle λ (= a tanl π dm ) of the cew. Once the tightening toque i eleaed, the fictional component of the peload diminihe, and the cew peload duing patient ue,, i detemined fom the fee body diagam given in igue 3b. Duing looening, the fiction foce act in the oppoite diection a compaed to the tightening. he cew peload duing looening can be detemined fom the igue 3c. 7

8 ightening oque he total tightening toque ovecome the eitive toque value equied to cew-in the IS abutment hould and c due to fiction in the cew thead and the conical (tapeed) inteface, epectively (igue 4), = +. (2) c he eitive toque in the cew thead can be calculated by the powe cew fomula 16 fo aiing a load, d l+ πµ d ecα = 2 πdm lecα m k m (3) whee d m i the mean diamete of the cew, µ k i the kinetic fiction coefficient, α i the thead angle and l i the lead of the cew. Note that vetical eiting load i ued in thi equation, a it i equal to the cew peload a mentioned above. he vetical component of the eiting foce in the tapeed ection, duing tightening i detemined fom igue 4a a, = Ninθ + µ Ninλcoθ (4) whee the kinetic fiction coefficient µ k i ued, a cew tightening i a dynamic poce. In ode to find an expeion fo the eitive toque k c in the conical ection of the abutment, the fiction foce on the tapeed ection ae conideed. he hoizontal component of the fiction foce, µ Ncoλ, in the conical inteface, hown in igue 3d, eit the tightening toque. he toque equied to ovecome thi fiction foce i found a follow 14, 8

9 ( c coθ 2 2πµ ( ) ( ) 0 ) coλ 1 πµ ke zcin2θcoλ { cinθ 2( b 3 ) in ( 4 in ) 4 ( )} 2 ab c θ ab c θ ab b 2 ab = b zp z dz c k c = + + 8b 2 whee P c i the contact peue whoe magnitude vaie in the z-diection a decibed by Bozkaya and Müftü 14. An equation fo the total tightening toque i obtained by combining equation (1)-(5), (5) dm πµ kdmecα + l = + 2 π dm µ klecα πµ ke zin2θcoλ 8 c 2 b2 { 2 2 ( ) 2 2 cinθ 2( b 3 in 4 in 4 } 2 ab) c θ ab + c θ + ab( b 2 ab) whee the axial component of eitive foce (peload) duing tightening equation (4). (6) i given by ooening oque An expeion fo the total looening toque, which equal the um of the eitive toque value in the cew thead and in the cone found by a imila appoach. he total looening toque i, c due to fiction, can be = +. (7) c he eitive toque in the cew thead i calculated fom the powe cew fomula. he fee body diagam given in igue 3c how that the peload at the onet of looening i expeed a, = Ninθ µ Ninλcoθ (8) 9

10 whee the tatic fiction coefficient µ i ued at the onet of looening. Note that duing looening, the fiction foce act in oppoite diection a compaed to the tightening cae igue 3d. hi eult in the negative ign fo the fictional component in thi equation. Inpection of Eqn (8) how that the vetical eiting foce in the cone duing looening could take a poitive o negative value, depending on the magnitude of the fiction coefficient µ, tape angle θ and cew lead angle λ. Poitive value of implie that the eultant foce in the conical intefeence i in the diection of the cew motion and negative value of implie that the cew thead have lot contact. Hence, the toque fomula equied to lowe a load hould be ued when > 0, and no toque i tanfeed to the cew thead when < 0. oque in the cew thead due to the peload i found fom the powe cew fomula fo loweing a load, 16 d m πµ dmecα l = H 2 π dm + µ lecα ( ) (9) whee H i the Heaviide tep function defined a; ( ) H = 1 when > 0 and ( ) H = 0 when < 0. he eitive toque in the cone c i obtained by uing the ame pocedue a in the cae of tightening toque given in Eqn (5), by uing the tatic fiction coefficient µ intead of the dynamic fiction coefficient µ k, { inθ 2( ( ) } ) inθ 4 inθ 4 ( 2 2 ) 2 2 πµ E z in2θcoλ = b + + b c c 2 c ab c ab c ab ab 8b 2 he total looening toque i obtained fom Eqn (7) - (10) a follow,. (10) 10

11 dm πµ dmecα l = H( ) + 2 π dm + µ lecα πµ E zin2θcoλ 8 c 2 b2 { 2 2 ( ) 2 2 cinθ 2( b 3 in 4 in 4 } 2 ab) c θ ab + c θ + ab( b 2 ab) whee the axial component of eitive foce duing looening (11) i given by equation (8). he efficiency of IS connection i defined a the atio of the tightening toque to the looening toque, η =. (12) RESUS he paamete, given in able 1, choen fo the cae tudy ae imila to a 4.8 mm diamete II implant. he popetie of the cew in thi implant ae a follow; mean cew diamete d m = mm; cew pitch l = 0.44 mm; cew lead angle? = 9.11 o ; and, the cew thead angle, α = 30 o. he Efficiency of the Attachment he efficiency of the ytem, a defined by Eqn. (12) i plotted a a function of the tatic µ and kinetic µ k fiction coefficient and the tape angle θ in igue 5. Pediction peented in igue 5a how that the efficiency of the ytem ha a tonge dependence on the kinetic fiction coefficient than the tatic fiction coefficient. o example, when tatic and kinetic fiction coefficient ae equal, and vay in the ange, the efficiency vaie between ; howeve, when kinetic fiction coefficient i 70% of the tatic fiction coefficient, the efficiency vaie between Accoding to equation (6) the kinetic fiction coefficient only affect the tightening 11

12 toque. heefoe, high efficiency i obtained if the kinetic fiction coefficient duing tightening i malle than the tatic fiction coefficient. Maximum efficiency i obtained when µ i between 0.3 and 0.4. igue 5a alo how the eult of the expeimental tudie by Noton 7, Squie et al. 6 and Sutte et al. 8 he compaion how that the eult pedicted by equation (12) and the expeiment agee favoably. igue 5b, whee the efficiency i plotted a a function of the tape angle θ fo diffeent fiction value, can be ued at the deign tage of a IS type abutment. In geneal, thi figue how that the efficiency of the ytem i educed at lage tape angle. o example, fo the cae whee µ = µ k = 0.5 the efficiency dop fom 0.96 to a the tape angle inceae fom 1 o to 10 o. he lope change obeved nea θ = 4.6 o in thi cuve coepond to the cae whee the cew peload become zeo, a pedicted by Eqn. (8). When the cew peload vanihe, the implant-abutment connection i povided by the tapeed intefeence fit (I) alone. A cloe inpection of thi figue how that the condition whee the change fom IS type to I type connection mechanim occu at µ = 0.3 fo a 2.8 o tape, at µ = 0.5 fo a 4.6 o tape, and at µ = 0.7 fo a 6.2 o tape. hu it can be een that a high fiction coefficient i neceay if a lage tape angle i choen in the deign of the IS type abutment. Effect of Sytem Paamete he tightening and looening toque fomula developed hee povide a elatively imple way of aeing the effect of the geometic and mateial popetie on thee toque. o example, the magnitude of the tightening toque and looening toque, found in Eqn (6) and (11), depend on the paamete?z and E, linealy; on the 12

13 paamete b 2, ab paabolically; on the paamete c in a cubic manne; on the paamete? and λ tigonometically; and on the paamete µ k, µ in a non-linea manne. he detail of thee functional dependence ae given next in igue 6. igue 6a how the effect of diffeent tape angle on the tightening toque and the looening toque fo µ k = µ = 0.3, 0.5 and 0.7. hi figue indicate that the tightening toque i alway geate than the looening toque when the kinetic and tatic fiction coefficient ae identical. he diffeence between the tightening and looening toque value inceae fo lage tape angle and at highe fiction coefficient value. Note that the tightening toque value epoted in thi figue ae conevative value, a the kinetic fiction coefficient i taken to be the ame a the tatic fiction coefficient. Howeve, the figue can be ued a a guide in the deign of the new IS type abutment. Moe detail on the value can be eaily obtained by uing Eqn. (11) fo the cae when kinetic fiction coefficient i diffeent than the tatic one. igue 6b how the vaiation of tightening and looening toque value with the contact length of the tapeed ection of the abutment fo thee diffeent fiction coefficient value. he tightening toque and looening toque depend on c linealy, a depicted in thi figue. Howeve, the effect of fiction coefficient fo a given toque value i tong. o example, if a clinically elevant tightening toque value of = 400 N.mm i conideed, the contact equied contact length change fom c = 0.35 mm fo µ = 0.7 to c = 0.85 mm fo µ = 0.3. igue 6c how the vaiation of the tightening and looening toque value with the oute adiu b 2 of the implant. hi figue how that fo lage adiu implant a highe toque value i equied to tighten the implant. he looening toque follow the 13

14 ame tend, howeve it value i pedicted to be lowe than the tightening toque when the kinetic and tatic fiction coefficient ae equal. Bozkaya and Müftü 14 have hown that, in the tapeed ection, the contact peue between the implant and the abutment inceae with inceaing implant adiu. hu lage nomal and fictional foce develop in the inteface, eulting in inceaed toque value. igue 6d how the vaiation of the tightening and looening toque value a a function of coefficient of fiction, fo the cae whee µ = µ k. he toque value equied to tighten and looen the abutment inceae with inceaing fiction coefficient. he dependence i nealy linea in the ange of fiction coefficient (i.e., ) ued in thi figue. A elation between the tightening toque and the looening toque can be obtained fom equation (6) and (11), by noting that z i common in both elation. hi how that looening toque i linealy popotional to the tightening toque a hown in igue 6e. hi finding i in ageement with the expeimental data by Noton 7 howing a linea elation between tightening and looening toque. he lope of the cuve, which i equal to the efficiency, i lightly diffeent which may tem fom the diffeence in kinetic and tatic fiction value. Scew Peload v. oque he cew peload a a function of elevant toque value can be obtained fom equation (6) and (11). Vaiou peload condition have been decibed in igue 7; the peload duing tightening, the peload duing looening, and the peload when no toque o biting foce ae applied on the ytem ae plotted a a function of toque fo 14

15 µ = 0.3 and 0.5, in igue 7. hi figue how that, in geneal, the cew peload i linealy popotional to the applied toque. o a given toque value, the highet peload occu duing tightening; afte the eleae of the tightening toque, the cew i ubjected to peload. hi i the "eated" peload of the cew. he peload become even lowe duing looening. iction ha an inteeting effect on the peload; fo a given toque value, the peload educe a the fiction coefficient i inceaed. o example at 350 N.mm the peload move fom 100 N to 60 N, a the fiction coefficient i inceaed fom 0.3 to 0.5. Note that Mez et al. 4 pedicted 53 N of peload, by modeling a 12 mm long, 8 o tape, IS type II implant with non-linea finite element analyi. 4 he peload value of 60 N, pedicted by the analytical method intoduced hee, i emakably cloe to thei value conideing the aumption made in thi pape. Ditibution of oque he tapeed uface of the IS type abutment povide a geat deal of fictional eitance a compaed to the fictional eitance on the cew thead. hi i evidenced by the plot given in igue 8, whee the pecentage of the total tightening toque caied by the tapeed ection a a function of fiction coefficient µ and tape angle θ ae hown. In igue 8a, it i een that, the cone caie 87-92% of the total tightening toque duing tightening, when the tatic fiction coefficient µ i changed between 0.1 and 0.9. he kinetic fiction µ k coefficient ha a elatively mall effect on thi pecentage. he effect of the tape angle θ on the tape total atio duing tightening i hown in igue 8b. hi figue how that in a IS type abutment with a malle tape angle moe of the 15

16 total toque i caied by the tapeed ection, in contat to lage tape angle. he ange of tape total atio i between 88-96% depending on the value of tatic fiction coefficient µ. Duing looening, the fiction foce in the cew thead act in a diection to educe the cew peload a evidenced by equation (8). hu by vaying the tatic fiction coefficient µ o the tape angle θ it i poible to elieve the peload. When thi happen all of the toque in the IS type abutment i caied by the tapeed ection, and the become one. he condition which caue thi ae identified in igue 8a and tape total b. In paticula, igue 8a how that fiction coefficient value le than 0.15 would caue the lo of peload duing looening fo an 8 o tape. he effect of tape angle θ on the lo of peload depend on the value of the tatic fiction coefficient µ a hown in igue 8b; inceaing fiction coefficient value allow ue of lage tape angle befoe cew peload i lot duing looening. Alo low tatic coefficient of fiction in the cew thead µ may caue the cew toque to be negative, contibuting to the looening of the attachment. hi happen when the tatic fiction coefficient µ i malle than 0.15 cauing the tape total to be lage than one. DISCUSSION he geneal ange of efficiency, pedicted to be , fo the ange of paamete conideed in thi pape, match cloely the expeimental eult. 6-8 he only condition that caue the efficiency to be geate than 1.0 i encounteed when the kinetic coefficient of fiction i taken 10% malle than the tatic coefficient of fiction. he efficiency became a low a 0.85 fo vey low value of the coefficient of fiction, uch 16

17 a 0.1. he efficiency alo depend on the tape angle; an inceae in tape angle fom 1 o to 10 o eult in a deceae in the efficiency, fom 0.97 to 0.9, depending on the value of the fiction coefficient. Othe caue fo futhe loe known a embedment elaxation which caue 2-10% eduction in the peload have been epoted. 2 Iue elated to manufactuing toleance, uface oughne, and ceep of uface apeitie that ae not captued by the analytical method peented hee. he behavio of the IS type of abutment attachment method i govened by the tapeed ection of the abutment, a a lage faction of the looening and tightening toque value ae ued to ovecome the fiction in the tapeed ection. he analytical method demontated that ove 86% of the tightening toque, and ove 98% of the looening toque ae balanced by the fictional foce in the tapeed ection. hi tudy clealy how that fiction coefficient tongly affect tightening and looening toque value; when fiction coefficient i high the tightening toque value equied to ecue the abutment may become too high, to be clinically afe; on the othe hand low fiction coefficient doe not eem to have an obviou advee effect. Nevethele, it i typically difficult to detemine the fiction coefficient exactly. heefoe, a magin hould be built into the deign of the IS type abutment. ACKNOWEDGMEN he autho would like to thank M. ed Weekley (United itanium Inc., Woote, OH, USA) fo hi valuable dicuion elated to thi pape and acknowledge the uppot of Bicon Implant (Bicon Inc., Boton, MA, USA). 17

18 REERENCES 1. Scacchi M., Mez BR, Schä A.R., he development of the II Dental Implant Sytem. Clin Oal Imp Re 11(Suppl.), Geng J., an K., iu G., Application of finite element analyi in implant dentity: A eview of the liteatue. J Pothet Dent 85, Schwaz, M.S Mechanical complication of dental implant. Clin Oal Impl Re 2000; 11(Suppl.), Mez B.R., Hunenbat S., Bele U.C., Mechanic of the implant-abutment connection: An 8-degee tape compaed to a butt joint connection. Int J Oal Maxillofac Implant, 15, Mangano C., Batolucci E.G., Single tooth eplacement by moe tape connection implant: A etopective tudy of 80 implant. Int J Oal Maxillofac Implant, 16, Squie R.S., Pote W.J., aylo.d., Removal toque of conical, tapeed implant abutment: he effect of anodization and eduction of uface aea. Int J Oal Maxillofac Implant, 17, Noton M.R., Aement of cold welding of the intenal conical inteface of two commecially available implant ytem. J Pothet Dent, 81, Sutte., Webe H.P., Soenen J., Bele U., he new etoative concept of the II Dental Implant Sytem: Deign and engineeing. Int J Peiodont Ret Dent, 13,

19 9. Noton M.R., In vito evaluation of the tength of the conical implant-toabutment joint in two commecially available implant ytem. J Pothet Dent, 83, Guimaãe P.M., Nihioka R.S., Bottino M.A., Analyi of implant/abutment maginal fitting. Pó-Gad Rev ac Odontal São Joé do Campo, 4, Janen V.K., Richte E.J., Micobial leakage and maginal fit of the implantabutment inteface. Int J Oal Maxillofac Implant, 12, Beeding.C., Dixon D.., Nelon E.W., ietge J.D., oque equied to looen ingle- tooth implant abutment cew befoe and afte imulated function. Intenational Jounal of Pothodontic, 6, O'Callaghan J., Goddad., Biichi R., Jagodnik J., Wetbook S., Abutment hammeing tool fo dental implant. Ameican Society of Mechanical Enginee, IMECE-2002 Poceeding Vol. 2, Nov , 2002, Pape No. DE Bozkaya D., Müftü S., Mechanic of the tapeed intefeence fit in dental implant. J Biomech, 36:11, Bozkaya D., Müftü S., Efficiency conideation fo the puely tapeed intefeence fit (I) abutment ued in dental implant. Jounal of Biomechanical Engineeing, ubmitted fo eview, Shigley J.E. and Michke C.R., Mechanical Engineeing Deign, 5 th edition, McGaw Hill, Boton. 19

20 it of igue igue 1 Vaiou implant-abutment attachment method. igue 2 he geometic paamete that affect the mechanic of the IS type abutmentimplant attachment method. igue 3 a) ee body diagam (BD) of the tape integated cew-in (IS) abutment duing tightening. b) he BD of the tapeed ection of the IS abutment. c) he BD of the cew ection of the IS abutment. Note that the total tightening toque i equal to the toque equied to tighten the tapeed ection and the cew ection igue 4 he BD diagam of the tapeed ection of the IS type abutment duing tightening (a), egula patient ue (b), and looening (c) give the coeponding petenion level, and caued in the cew a hown in thi figue. d) iction foce in tightening. igue 5 he efficiency of the attachment with epect to diffeent paamete. ape angle?, fiction coefficient µ ae the ignificant paamete affecting the efficiency of the attachment. igue 6 he effect of vaiou paamete on looening and tightening toque. igue 7 Scew peload a a function of extenal toque fo two diffeent fiction coefficient. igue 8 he pecentage of the total tightening toque caied by the tapeed ection a a function of a) fiction coefficient and b) tape angle. c. it of able able 1 Deign paamete of the tapeed inteface in a4.8 mm II ytem (Implant: S; Abutment: ). *he tatic fiction coefficient wa fixed at 0.5 fo analyzing the effect of diffeent tatic and kinetic fiction offet value. 20

21 Implant Paamete q µ µ [ o k/ c?z b 2 E ] (mm) (mm) (mm) (MPa) ab (mm) II Bae Value 8 0.3, 0.5* x Range N/A *he tatic fiction coefficient wa fixed at 0.5 fo analyzing the effect of diffeent tatic and kinetic fiction offet value. able 1 Deign paamete of the tapeed inteface in a 4.8 mm II ytem (Implant: S; Abutment: ). 21

22 Ankylo II Bicon Nobel Biocae igue 1 Vaiou implant-abutment attachment method 22

23 abutment z θ δ b 1 (z) c ab d m b 2 implant igue 2 23

24 c µninλ N θ N a) BD in tightening b) BD duing ue c θ q θ µninλ N µninλ µn λ l N µncoλ c) BD in looening d) iction foce in tightening igue 3 he BD diagam of the tapeed ection of the IS type abutment duing tightening (a), egula patient ue (b), and looening (c) give the coeponding pe-tenion level, and caued in the cew a hown in thi figue. d) iction foce in tightening. 24

25 c θ µ Ninλ N θ µ Ninλ N d m µ n P a) b) c) λ n igue 4 a) ee body diagam (BD) of the tape integated cew-in (IS) abutment duing tightening. b) he BD of the tapeed ection of the IS abutment. c) he BD of the cew ection of the IS abutment. Note that the total tightening toque i equal to the toque equied to tighten the tapeed ection and the cew ection. c 25

26 Efficiency, h η 1.2 c y, n 1.15 e ci 1.1 fi E µ k =0.7µ µ k =0.9µ µ k =µ Sutte 8 Squie 6 Efficiency, η µ =µ k =0.7 µ =µ k =0.5 µ =µ k = Noton Static Coefficient of iction, µ ape Angle, θ a) b) igue 5 he efficiency of the attachment with epect to diffeent paamete. ape angle?, fiction coefficient µ ae the ignificant paamete affecting the efficiency of the attachment

27 µ = µ = 0.7 oque (N.mm) µ = 0.5 oque (N.mm) µ = 0.5 µ = µ = ape Angle, θ Contact ength, c (mm) a) b) µ = oque (N.mm) µ = 0.5 µ = 0.3 oque (N.mm) t Oute Implant Radiu, b 2 (mm) Coefficient of iction, µ c) d) 500 hi wok II Implant 8 o tape, (Expeimental) Noton 8 ooening oque, (N.mm) igue ightening oque, t (N.mm) e) 27

28 µ k = µ = 0.3 µ k = µ = 0.5 EA Solutionfo µ = 0.5 by Mez et al. 8 Peload (N) ightening Peload, Peload, ooening Peload, oque (N.mm) igue 7 Scew peload a a function of extenal toque fo two diffeent fiction coefficient ooening oque ooening oque 0.96 µ k = µ 0.96 ightening oque tape / total ightening oque µ k = 0.9µ µ k = 0.7µ tape / total µ =0.3 µ =0.5 µ = Static Coefficient of iction, µ a) ape Angle, θ b) igue 8 he pecentage of the total tightening toque caied by the tapeed ection a a function of a) fiction coefficient and b) tape angle. 28