Impact of dental cement on the peri-implant biofilm-microbial comparison of two different cements in an in vivo observational study.

Impac o den al cemen on he pe i-implan issue Mic obial compa ison o wo di e en cemen s in an in- i o obse a ional s udy Ko sch M., Ma en S. M., Wal he W., Vi al M., Piepe D.H., Doe sch A. Au ho s’ a ilia ions: D . Michael Ko sch -Den al Academy o Con inuing P o essional De elopmen , Ka ls uhe Lo enzs asse 7, 76135 Ka ls uhe, Ge many -P i a e p ac ice, Cen e o Implan ology and O al Su ge y, 69120 Heidelbe g, Ge many -Clinic o Ope a i e Den is y, Pe iodon ology and P e en i e Den is y, Uni e si y Hospi al, Saa land Uni e si y, Building 73, 66421 Hombu g, Ge many P o . D . Win ied Wal he -Den al Academy o Con inuing P o essional De elopmen , Ka ls uhe Lo enzs asse 7, 76135 Ka ls uhe, Ge many D . And eas Doe sch, Silke-Ma eike Ma en - Ins i u e o Func ional In e aces, Ka ls uhe Ins i u e o Technology (KIT), Ka ls uhe, Ge many P o . D . Die ma H. Piepe , D . Ma ius Vi al. - Mic obial In e ac ions and P ocesses Resea ch G oup, Helmhol z Cen e o In ec ion Resea ch, B aunschweig, Ge many. Co esponding au ho : D . med. den . Michael Ko sch, M.A. Den al Academy o Con inuing P o essional De elopmen Lo enzs asse 7 76135 Ka ls uhe Ge many Phone: +49-721-9181-200 Fax: +49-721-9181-222 E-mail: michae[email p o ec ed] Au ho Con ibu ion S a emen : Michael Ko sch, And eas Doe sch, Silke-Ma eike Ma en: Design, da a collec ion, s a is ics, da a analysis/in e p e a ion, d a ing a icle, app o al o he submi ed e sion. No con lic o in e es . Win ied Wal he , Die ma Piepe , Ma ius Vi al: Design, s a is ics, d a ing a icle, app o al o he submi ed e sion. No con lic o in e es . Abs ac Backg ound Unde ec ed excess cemen in cemen ed ixed implan -suppo ed es o a ions in ol es he isk o pe i- implan in lamma ion. I is unclea wha in luence a e ision o he sup as uc u e including he emo al o exis ing excess cemen will ha e on he pe i-implan issue and i s mic obial bio ilm. Pu pose The aim o he s udy was o in es iga e he impac o wo di e en cemen s on he pe i-implan bio ilm. Me hods In an obse a ional s udy he sup as uc u es o 34 pa ien s wi h cemen ed ixed implan -suppo ed es o a ions we e e ised. In 20 pa ien s a me hac yla e cemen (PIC) and in 14 pa ien s a zinc oxide eugenol cemen (TB) was used. A e e ision TB was used o ecemen a ion. Du ing e ision and ollow-up one yea a e , mic obial samples we e ob ained. Resul s Excess cemen was ound in 12 (60%) o he 20 pa ien s wi h PIC. Suppu a ion was obse ed in wo (25%) implan s wi h PIC wi hou excess cemen (PIC-) and in all 12 (100%) implan s wi h PIC and excess cemen (PIC+). Implan s cemen ed wi h TB had nei he excess cemen no suppu a ion. The axonomic analysis o he mic obial samples e ealed an accumula ion o o al pa hogens in he PIC pa ien s independen o he p esence o excess cemen . Signi ican ly ewe o al pa hogens occu ed in pa ien s wi h TB compa ed o pa ien s wi h PIC. TB was used in all cases (PIC and TB) o ecemen a ion. In he ollow-up check, suppu a ion was no ound a ound any o he implan s wi h PIC-, only a ound one implan wi h PIC+ and a ound one implan wi h TB. Bac e ial species associa ed wi h se e e pe iodon al in ec ions ha we e abundan in PIC- and PIC+ samples be o e he e ision we e educed a e one yea o le els ound in he TB samples. Conclusion The e ision o he sup as uc u es including he emo al o excess cemen and he ecemen a ion wi h TB ha e a dis inc in luence on he pe i-implan issue and i s mic obial bio ilm. Key wo ds: den al cemen s, bio ilms, molecula biological analysis, in- i o obse a ional s udy, implan In oduc ion The cemen a ion o ixed sup as uc u es on implan s in ol es he isk o excess cemen emaining in he pe i-implan sulcus 1-3. The p e alence o his complica ion is epo ed o amoun o up o 60% 4. Excess cemen a o s he o ma ion o a bio ilm 5 and may lead o pe i-mucosi is, pe i-implan i is o e en he loss o he implan i his complica ion emains unde ec ed . The longe he ime he excess cemen has s ayed in he pe i-implan sulcus, he g ea e he isk o pe i-implan in lamma ion 8. The consequence may be a highe deg ee o pe i-implan bone loss 9. Unde ec ed excess cemen will cause cemen -associa ed pe i-implan in lamma ion a ound app ox. 80% o he implan s . Fo his eason many s udies we e made dealing wi h he a oidance o excess cemen . One op ion is he modi ica ion o he den al es o a ion. D ainage holes in he abu men and sup as uc u e can educe he amoun o excess cemen a e cemen a ion 10-12. O he publica ions desc ibe cemen a ion p o ocols minimizing he isk o submucosal excess cemen and ecommend ha du ing cemen a ion he sup as uc u es should only pa ly, no comple ely, be illed wi h cemen 2. The empo a y ex ao al cemen a ion on duplica e implan abu men s can ma kedly educe he isk o excess cemen when he den al es o a ion is immedia ely inse ed in he mou h be o e he cemen has ully ha dened . Howe e , none o hese p o ocols will elimina e he isk comple ely 15. The bac e ial coloniza ion o lu ing cemen s was con i med in se e al in- i o s udies 16-18. Cemen s on a me hac yla e basis seem o be mo e p one o i han cemen s on a zinc oxide eugenol basis . In pa ien s wi h cemen -associa ed pe i-implan i is he emo al o excess cemen om he sulcus will elimina e he pe i-implan i is in abou 75% o he cases . These s udies, howe e , co e an obse a ion pe iod o no mo e han 3-4 weeks a e cemen emo al. The e a e indica ions ha ce ain cemen s will lead o pe i-implan in lamma ion e en in he absence o excess cemen . I is he e o e unclea wha long- e m in luence he emo al o excess cemen will ha e on he pe i-implan issue. On he o he hand, he ins umen a ion o he abu men using cu e es and scale s may comp omise i s su ace 21. Roughening he abu men su ace can i sel again a o he o ma ion o a bio ilm 22. Ou hypo hesis was ha di e en ypes o cemen ha e a ying in luence on he pe i-implan bio ilm. The aim o he p esen obse a ional s udy was o in es iga e he e ec s o excess cemen emo al on he clinical indings and he mic obial pe i-implan bio ilm. Ma e ial and me hods Be ween Ap il 2009 und Feb ua y 2010, a me hac yla e-based empo a y cemen (P emie Implan Cemen (PIC), P emie ® Den al P oduc s Company, Plymou h Mee ing, USA) was used o he ixa ion o sup as uc u es on implan s. A e some mon hs se e al pa ien s de eloped pe i-implan in lamma ions which we e connec ed wi h unde ec ed excess cemen . Due o hese complica ions, a empo a y cemen based on zinc oxide eugenol (Temp Bond (TB), Ke Syb on Den al Speciali ies, Glendo a, USA) was used om Ma ch 2010. Bo h cemen s we e no adiopaque a he ime o he s udy. In a clinical obse a ional s udy, he in luence o he ype o cemen used o ixed implan -suppo ed es o a ions on he pe i-implan issue and he mic obial bio ilm was o be in es iga ed. Pa ien s' sup as uc u es ha had been ixed wi h one o he wo cemen s men ioned (PIC and TB) we e e ised be ween Sep embe and Decembe 2013. In he e ision he clinical indings we e documen ed and mic obial samples aken. As in some cases PIC had caused pe i-implan in ec ions and we had s opped using i in ou clinic in Ma ch 2010, all sup as uc u es ha had p e iously been ixed wi h PIC o TB we e ecemen ed wi h TB. In he clinical ial we we e able o p o e ha PIC and TB di e in hei e ec on he pe i-implan issue and he submucosal bio ilm. These esul s ha e al eady been published 5. Implan s wi h PIC-cemen ed sup as uc u es demons a ed signi ican ly mo e pe i-implan in lamma ions and o al pa hogens han implan s wi h TB-cemen ed sup as uc u es. Wha was unclea was whe he , a e e ision and ecemen a ion wi h TB, he pe i-implan issue a ound implan s wi h PIC will heal and a heal hy mic o lo a will again de elop a ound such implan s. The p esen ial was made wi h he aim o in es iga ing, in cases o cemen -associa ed pe i- implan i is, he in luence o e ision and ecemen a ion wi h TB on he pe i-implan issue and he mic obial bio ilm. Thus, he pa ien s whose sup as uc u es had been e ised be ween Sep embe and Decembe 2013 we e ollowed up in he pe iod om No embe 2014 o Janua y 2015. Inclusion and exclusion c i e ia: Pa ien s whose sup as uc u es we e e ised be ween Sep embe and Decembe 2013 quali ied o inclusion. All hese pa ien s had ixed implan -suppo ed sup as uc u es cemen ed wi h ei he PIC o TB. A he ime o e ision he sup as uc u e needed o be in si u o a leas 3.5 yea s. In addi ion, all hese cases needed o be ully documen ed om he ime o inse ion o he den al es o a ion in he mou h. Sup as uc u es ha demons a ed decemen a ion a e inse ion o he den al es o a ion o a e e ision we e excluded om he ial. All pa ien s we e ully in o med in ad ance abou he planned s udy and he clinical p ocedu e. A signed In o med Consen Fo m was he condi ion o pa icipa ion in he ial. The ins i u ional e iew boa d o he Medical Council o he Saa land examined and con i med he p ojec (app o al was g an ed on No embe 24, 2014, e e ence no. 146/11). Clinical p ocedu e o e ision, documen a ion o clinical indings and sampling - Be o e he e ision o he sup as uc u e, a pool sample was aken wi h s e ile pape poin s om he pe i-implan sulcus a ound each implan . Any exis ing signs o in lamma ion (pocke suppu a ion) we e documen ed. - A e ision, he sup as uc u e was emo ed wi h den al o ceps o a hook. In all cases he es o a ions could be emo ed wi hou being damaged. A e e ision o he sup as uc u es including he abu men s, he excess cemen a ound each implan was documen ed. - Finally, he pe i-implan issue was insed wi h chlo hexidine 0.12 % and he sup as uc u e was ecemen ed wi h TB cemen . Clinical p ocedu e o ollow-up, documen a ion o clinical indings and sampling - A pool sample was aken wi h s e ile pape poin s om he pe i-implan sulcus a ound each implan . Any exis ing signs o in lamma ion (pocke suppu a ion) we e documen ed. - Finally, he pe i-implan issue was insed wi h chlo hexidine 0.12 % S udy popula ion (Fig. 1) Be ween Janua y and May 2010, a o al numbe o 38 pa ien s had ecei ed p os he ic es o a ion using empo a y me hac yla e cemen (PIC) o a zinc oxide eugenol cemen (TB). The sup as uc u es we e e ised be ween Sep embe and Decembe 2013. One yea a e e ision he apy 34 pa ien s could be ollowed up while he emaining 4 pa ien s decided o op ou o he s udy. PIC popula ion: This coho included 20 pa ien s (14 men, 6 women) aged be ween 19 and 77 yea s (a e age age 60.4 yea s) a he ime o sup as uc u e cemen a ion. The a e age e en ion ime (pe iod be ween cemen a ion and e ision) o he sup as uc u e was 4.1 yea s. In 12 (60%) o hese pa ien s unde ec ed excess cemen was iden i ied in he pe i-implan issue a e ision. Based on his inding, he pa ien s we e subdi ided acco ding o he p e alence o excess cemen . G oup 1 [PIC-] (PIC popula ion wi hou ini ially unde ec ed excess cemen ): This g oup included 8 pa ien s (4 men, 4 women). The a e age age was 62.6 yea s. G oup 2 [PIC+] (PIC popula ion wi h ini ially unde ec ed excess cemen ): This g oup included 12 pa ien s (10 men, 2 women). The a e age age was 58.8 yea s. TB popula ion: In his coho he e we e 14 pa ien s (7 men, 7 women). A he ime o cemen a ion he pa ien s' age was be ween 34 and 72 yea s (a e age age 60.6 yea s). The a e age e en ion ime o he sup as uc u e was 3.7 yea s. A he ime o e ision, unde ec ed excess cemen was no ound in he pe i-implan issue o any o hese pa ien s. Fo his eason all 14 pa ien s we e combined in G oup 3 [TB]. Fo he mic obial analysis o he pe i-implan issue, bac e ial samples we e ob ained by p obing he pe i-impan pocke o a o al o 34 pa ien s using s e ile pape poin s and analyzed o axonomic composi ion by sequencing he V1-V2 a iable egions o he 16S RNA gene. Mic obial me hods DNA ex ac ion Pape poin ips we e cu and placed in s e ile 1.5 mL ubes, co e ed wi h 1 mL nuclease ee wa e (Li e echnologies, Ca lsbad, CA) and o exed o 10 s. Fo debonding o bio ilm mic obes, he samples we e ea ed o 2:30 h on a he momixe (Eppendo Ins umen s, Hambu g, Ge many) a 22 °C and 1400 pm, ollowed by 10 s o exing, 5 min sonica ion a 43 kHz and again o exed o 10 s. The supe na an s we e collec ed and cen i uged o 10 min a 13,300 pm (Bio uge Pico, He aeus). All supe na an s we e disca ded and he pelle s s o ed o 24 h a -80°C. The collec ed pelle s o he supe na an we e ea ed wi h 180 µL lysozyme solu ion (20 mg/mL, SIGMA-Ald ich, Tau ki chen, Ge many; 20 mM T is-HCl, pH 8.0, 2 mM EDTA, 1.2% T i on) unde shaking a 37°C o 2:15 h, ollowed by p o einase K diges ion (20 µL p o einase K and 200 µL bu e AL) o 1:30 h while shaking a 56°C. DNA was ex ac ed using comme cial ex ac ion p o ocols o genomic DNA (QIAamp Mini Ki , Qiagen, Hilden, Ge many). Finally, he DNA was elu ed wi h 100 µL PCR-clean wa e and he concen a ion was quan i ied using he NanoD op equipmen (PEQLAB, E langen, Ge many). Amplicon lib a y p epa a ion and axonomic analysis o pa hogen g oups P e iously desc ibed p ime s o he V1 and V2 egion o he 16S RNA gene (27F and 338R) we e used o ampli ica ion and lib a ies p epa ed as p e iously desc ibed . Illumina sequencing and bioin o ma ic p ocessing o pai ed end eads (250 bp) was done as p e iously desc ibed wi h modi ica ions 23. Raw eads we e me ged and subsequen ly aligned using MOTHUR (go oh algo i hm using he SILVA e e ence da abase) p io o p e-clus e ing (allowing o 2 misma ches) 25 26 Phylo ypes exhibi ing an a e age abundance o ≥ 0.005% and a sequence leng h o ≥ 250bp we e conside ed o ollow-up analysis. A o al numbe o 996 di e en phylo ypes (OTUs) emained. Rela i e pe cen abundances we e used o u he analysis. Phylo ypes we e assigned o a axonomic a ilia ion based on he naï e Bayesian classi ica ion 27 wi h a h eshold o 80 % ollowed by manual cu a ion as p e iously desc ibed 23. To iden i y phylo ypes indica ing he p esence o he h ee species o he ed complex as de ined by Soc ansky and Ha ajee 28, i.e., Po phy omonas gingi alis, T eponema den icola and Tanne ella o sy hia, sequences o all isola es o he espec i e gene a a ailable om he RDP se e (h p:// dp.cme.msu.edu) we e sepa a ely downloaded. Those sequences co e ing he 16S RNA egion analyzed he e we e immed and aligned wi h amplicon sequences whe e he Bayesian classi ica ion has indica ed ha hey de i ed om membe s o he espec i e genus. Sequences we e aligned using MUSCLE 29 and phylogene ic analyses conduc ed in MEGA7 30. The e olu iona y his o ies o genes we e in e ed using he neighbo -joining me hod and he Jukes-Can o model. All posi ions con aining alignmen gaps and missing da a we e elimina ed only in pai wise sequence compa isons. Amplicon sequences we e hen assigned o o igina e om a p e iously desc ibed species i hey a e localized in a b anch suppo ed by high boo s ap alues (> 80) o med exclusi ely by membe s o ha species. S a is ical me hods The da a we e analyzed wi h IBM SPSS S a is ics 21 (IBM SPSS S a is ics, IBM, A monk, NY, USA). The di e ence in excess cemen be ween PIC and TB was analyzed using he Chi-squa ed es o s a is ical independence. The di e ences in he ela i e abundance o pa hogen g oups be o e and a e he cemen eplacemen we e analyzed using he Wilcoxon signed ank es , a non-pa ame ical es o he null hypo hesis ha he median o he dis ibu ion o di e ences is ze o. The esul ing P- alues we e co ec ed o mul iple es ing by using he Benjamini-Hochbe g me hod 31. A p incipal componen analysis o he ela i e abundances was pe o med using a singula alue decomposi ion algo i hm wi h cen e ing o he da a. The Wilcoxon signed ank es and he p incipal componen analysis we e pe o med using he sign ank and pca unc ions o he Ma lab S a is ics oolbox R2015a (Ma hwo ks Inc., Na ick, MA, USA). Resul s The wo popula ions PIC and TB we e homogeneous in e ms o gende dis ibu ion, a e age age and o al e en ion imes o he sup as uc u es, since no signi ican di e ences o hese ac o s we e ound (ANOVA es ). A he ime o e ision wo implan s (25%) in he PIC- g oup and all wel e implan s (100%) in he PIC+ g oup we e a ec ed by suppu a ion. In he TB g oup none o he 14 implan s had his complica ion. The di e ence be ween he h ee g oups was signi ican (Chi-squa ed wi h 2 d , 27,807; p< 0.001). The ollow-up one yea a e e ision p esen ed a comple ely di e en clinical pic u e. In he PIC- g oup he e was no implan wi h suppu a ion any mo e, and in he PIC+ g oup he e was jus one such implan . Howe e , one implan in he TB g oup also suppu a ed. The di e ence be ween he h ee g oups was no longe signi ican . Resul s o he mic obial e alua ion The axonomic analysis based on amplicons o he gene encoding he 16S ibosomal subuni iden i ied 996 indi idual phylo ypes ha we e assigned o 122 di e en gene a using he RDP classi ie . The subgingi al mic obio a ac oss all samples in his s udy is domina ed by he six phyla Ac inobac e ia, Bac e oide es, Fi micu es, Fusobac e ia, P o eobac e ia and Spi ochae es (Fig. 2). No ably, he di e en g oups o cemen ypes showed a much mo e simila axonomic composi ion a e he eplacemen o he cemen s by TB (Fig. 2, lowe panels). Be o e he eplacemen , he subgingi al mic obio a o implan s wi h PIC cemen (PIC- and PIC+) con ained la ge ac ions o Bac e oide es and Spi ochae es. These wo phyla include he h ee species ha a e classi ied as he “ ed complex” in he Soc ansky nomencla u e 28, namely Po phy omonas gingi alis, Tanne ella o sy hia (bo h Bac e oide es) and T eponema den icola (Spi ochae es). The ed complex bac e ia ha e been iden i ied as he majo pa hogens in se e e pe iodon i is and pe i-implan i is 28. They ep esen he majo i y o Bac e oide es and Spi ochae es sequences in he PIC cemen samples. An indi idual compa ison o he ela i e abundance o he h ee ed complex species in each o he di e en sample g oups con i ms ha he p e iously obse ed highe ela i e abundance o ed complex species 5 was di ec ly ela ed o he PIC cemen and e e ed back o alues simila o TB cemen samples a e PIC cemen was eplaced by TB cemen (Fig. 3 A and B 5). In e es ingly, h ee implan s wi h TB cemen exhibi ed an abundance o P. gingi alis ha was much highe han in o he implan s o his g oup, which emained a a high le el albei wi h some educ ion e en a e he eplacemen o he cemen by esh TB. In a leas one o hese cases he de ec ion o P. gingi alis can be ela ed o a documen ed pe iodon al in ec ion and hese esul s migh he e o e be un ela ed o he cemen ype. A p incipal componen analysis o all samples in he s udy was pe o med (Fig. 4) in analogy o he p e ious s udy, esul ing in a simila pa e n wi h h ee main “b anches” o da a poin s. Roughly, hese h ee g oups o pa ien s a e cha ac e ized by a subgingi al mic obiome domina ed by commensal o al bac e ia (lowe b anch in Fig. 4), Fusobac e ium nuclea um ( igh b anch) o bac e ia o he Soc ansky ed complex (uppe b anch). In acco dance wi h he educ ion o he Soc ansky ed complex a e implan e ision and eplacemen o he cemen , he la e g oup only con ains da a poin s e lec ing implan s (mos ly o he PIC-ex and PIC+ex g oups) be o e he e ision. Discussion The clinical pic u e o he TB popula ion and he PIC popula ion di e ed e y clea ly a he ime o e ision. A e an a e age e en ion pe iod o 4.1 yea s, excess cemen le in he sulcus caused pe i- implan suppu a ion in all cases, al hough 2 implan s (25%) wi hou excess cemen o which PIC had been used (PIC-) we e also a ec ed by suppu a ion. None o he implan s wi h TB-cemen ed sup as uc u es had excess cemen o suppu a ion. I is o be assumed ha cemen a ion wi h zinc oxide eugenol cemen can also lead o excess cemen 32, which, howe e , will appa en ly dissol e in con ac wi h he sulcus luid in he pe i-implan issue. In- i o s udies con i med his assump ion and could p o e ha , in con ac wi h a i icial sali a, zinc oxide eugenol cemen s a e showing signs o disin eg a ion a e a sho pe iod al eady 33. A ollow-up one yea a e e ision, he clinical pic u e o he PIC popula ion had comple ely changed. Only one implan o his popula ion s ill suppu a ed. I is o be assumed ha bo h he e ision o he den al es o a ions including he emo al o he excess cemen and he ecemen a ion wi h TB had an essen ial in luence on he clinical indings. We know o su e ha he wo p incipal componen s, i.e. zinc oxide and eugenol, in TB cemen ha e an e ec on he pe i-implan bio ilm. Zinc oxide is said o ha e an an imic obial ac i i y . Eugenol, an isola ed compound o clo es oil (Syzygium a oma icum), also has an an imic obial e ec as ha e many essen ial oils . Eugenol is able o inhibi he g ow h o a la ge numbe o mic oo ganisms wi hou being able o des oy hem . I has an an ibac e ial, an i i al as well as an an i ungal e ec 40-43. The clinical indings a e a ollow-up pe iod o one yea may be assumed o be s able and he esul o emo ing he excess cemen and changing he ype o cemen ( om PIC o TB) when he den al es o a ions we e ecemen ed in he e ision ea men . The o al mic obiome is ex emely di e se and la ge numbe s o di e en axa ha e been desc ibed in he li e a u e 44-46. The subgingi al plaque has been desc ibed as being domina ed by bac e ial species belonging mainly o i e o six phyla 46 ha we e also de ec ed in his s udy (Fig. 2). The p incipal componen analysis demons a ed ha he e is subs an ial a iance ac oss all samples ha is only pa ially co e ed by ou analysis (only ~ 30% o he o al a iance is explained by he i s wo p incipal componen s p esen ed in Fig. 4). A la ge p opo ion o his a iance migh be in luenced by ac o s ha a e beyond he scope o his s udy and he a ailable addi ional me ada a (including smoking, ecen an ibiosis and diabe es), could no be clea ly co ela ed wi h he da a (da a no shown). Ne e heless, he esul s suppo ed he connec ion be ween he abundance o pa hogenic bac e ia wi h he p esence o PIC and unde ec ed excess cemen . In he ini ial s udy o implan s wi h he di e en cemen ypes, a shi was obse ed owa ds a highe ela i e abundance o bac e ia belonging o he Soc ansky ed complex wi hin he subgingi al plaque ha was speci ic o he g oup o implan s wi h PIC cemen . Compa ing he axonomic esul s o hese implan s one yea a e he eplacemen clea ly shows ha he mic obiome has e e ed o a s a e ha closely esembles he composi ion o implan s wi h TB cemen (be o e and a e e ision) and is also in line wi h he subgingi al mic obiome published elsewhe e . This obse a ion clea ly con i ms ha he ed complex bac e ia a e speci ically mo e abundan when PIC cemen is used and ha he isk o an in ec ion o he pe i-implan issue can be s ongly educed by a oiding his cemen ype and eplacing i whe e i has al eady been applied. The esul s could be in luenced by he small g oup size which is a limi a ion o he s udy. Thus, implan s whose sup as uc u es we e ixed wi h a me hac yla e-based cemen appa en ly ha e mo e o al pa hogenic bac e ia in he pe i-implan sulcus han implan s ha we e cemen ed wi h zinc oxide eugenol cemen . In his espec he ma e ial p ope ies o zinc oxide eugenol a e pe ec ly sui able o he pe manen cemen a ion o ixed implan -suppo ed den al es o a ions. Zinc oxide eugenol cemen , howe e , is s a ed o be a empo a y lu ing cemen so ha i s use as a pe manen lu ing ma e ial is no in ag eemen wi h he p oduc desc ip ion. Compa ed o ha de cemen s, i s weake e en i e p ope ies, howe e , do no seem o be o clinical ele ance 47-49. The e o e he pe manen cemen a ion o ixed implan -suppo ed den al sup as uc u es wi h zinc oxide eugenol cemen is o be ecommended. Acknowledgemen s We hank Tama a S obl o suppo du ing sample and da a collec ion. Die ma H. Piepe and Ma ius Vi al we e suppo ed by iMed, he Helmhol z Associa ion’s Ini ia i e on Pe sonalized Medicine. Re e ences 1. Callan DP, Cobb CM. Excess cemen and pe i-implan disease. JIACD 2009; 1: 61-68.