Class II Resin Composites: Restorative Options

Transcription

1 Minesh Ptel Shmir B Meht nd Suir Bnerji Clss II Resin Composites: Restortive Options Astrct: Tooth-coloured, resin composite restortions re mongst the most frequently prescried forms of dentl restortion to mnge defects in posterior teeth. The ttinment of desirle outcome when plcing posterior resin composite restortions requires the clinicin to hve good understnding of the enefits (s well s the limittions) posed y this mteril, together with sound knowledge of plcement technique. Numerous protocols nd mterils hve evolved to ssist the dentl opertor with this type of demnding posterior restortion. With the use of cse exmples, four techniques ville re reported here. CPD/Clinicl Relevnce: This rticle explores vrying techniques for the restortion of Clss II cvities using resin composite. Dentl Updte 2015; 42: The prescription of direct plstic restortive mterils continues to e the primry choice for most dentl prctitioners for the mngement of crious lesions in the posterior dentition. This is lrgely on ccount of the conservtion of the residul dentl hrd tissues, the reltive economic enefits nd the progressive development of direct restortive mterils (especilly of the dhesive vriety). 1 Very few would contest the notion of silver mlgm eing populr (nd indeed successful) mteril in conservtive dentistry, with prescription record extending from the 1800s to the present time. 2 In recent yers however, Minesh Ptel, BDS(Lond), Surrey (Postgrd MSc in Aesthetic Dentistry, KCLDI), Shmir B Meht, BDS, BSc, MClinDent(Prosth), Senior Clinicl Techer, Dep Dir MSc Aesthetic Dentistry, Dept Conservtive & MI Dentistry, KCLDI nd Suir Bnerji, BDS, MClinDent MFDGP(UK), Progrmme Director MSc Aesthetic Dentistry, King s College London Dentl Institute, Floor 18, Tower Wing, Guy's Cmpus, St Thoms's Street, London, SE1 9RT, UK. prticulrly in light of the Minmt Trety (which mongst severl other ojectives ims to phse down the use of dentl mlgm), there hs een n interntionl prdigm shift concerning the plcement of silver mlgm restortions, with countries such s Norwy imposing complete n for the prescription of mlgm-sed restortions since 2011, primrily on ccount of environmentl concerns 3 nd move towrds less invsive protocols which egins to ddress the issues of restortive longevity versus tooth longevity over the lifetime of ptient. In Austrli, Government report pulished y working group for the NHMRC (Ntionl Helth nd Medicl Reserch Council) in Mrch 1999, descried reduction in the provision of dentl mlgm restortions y privte generl dentl prctitioners from 57.9% in to 28.0% in (when considering the totl numer of dentl restortions plced, inclusive of indirect restortions), therey representing reduction y lmost 50%. 4 The ltter trend ws suggested to e most likely to e ccounted for y n implementtion of more minimlly invsive philosophy y dentl prctitioners, lrgely rendered possile y dvnces tking plce in the understnding of resindhesive dentistry, with concomitnt increse in the numer of resin composite restortions douling over the sme time periods stted previously. In the UK however, the move towrds mlgm free prctice is tking plce t considerly slower pce. Whilst the teching of posterior restortions hs seen chnge in the UK dentl schools, dentl students continue to gin slightly more experience with the plcement of silver mlgm restortions nd directly onded resin composite restortions, respectively. 5 Indeed, it is estimted tht, in the UK, up to three-qurters of the restortions in posterior teeth re of the dentl mlgm vriety, with the nnul expenditure on dentl mlgm restortions eing likely to exceed 300 million in the short term, with 12 million mlgm restortions eing prescried on the Ntionl Helth Service in Englnd nd Wles y dentl prctitioners in the primry cre sector. 5 The populrity of dentl mlgm my e ccounted for y its eneficil mechnicl properties, in prticulr its compressive strength, together with hving higher tolernce Octoer 2015 DentlUpdte 721

2 Secondry cries Bulk restortive frcture Mrginl degrdtion Surfces wer Tle 1. A list of the most common resons for filure of posterior resin composite restortions (Mjör et l, 2000). 11 Figure 1. Cse 1: Pre-opertive. Figure 2. Cse 1: Cvity preprtion. for technique sensitivity, such s moisture tolernce nd plcement technique, economic enefits, nticteril ctivity nd proven record for success. 6 However, poor tensile strength, poor esthetic cceptnce, lck of intrinsic dhesive potentil nd environmentl concerns hve prompted the serch for lterntive mterils. 7 Resin composite is one such mteril. Directly onded posterior resin composite restortions hve ecome Figure 3. Cse 1: Completed restortion. Figure 4. Cse 2: Pre-opertive sitution. incresingly populr since the erly 1980s, prticulrly for the conservtive nd esthetic mngement of smll to medium sized cvities in posterior teeth. 4 Bonded restortions my lso provide mens of strengthening nd conserving remining tooth sustrte in the long term. 8 The durility or longevity of dentl mteril in the orl environment is often interpreted s guide to reltive success of its efficcy in the orl cvity. 9 Cross-sectionl retrospective studies (often undertken in the primry cre environment, with less well defined selection criteri nd protocols, respectively), sed on the survivl of posterior mlgm restortions, hve reported medin survivl times of etween 6.6 nd 14.0 yers, versus 3.3 to 4.7 yers for directly onded posterior resin composite restortions. 6 The principl cuses ttriuted to the resons for the higher filure rte of posterior resin composite restortions hve een listed in Tle 1. In contrst, nlogous longitudinl clinicl studies, with restortions eing plced y trined opertors, pplying consistent protocols nd creful selection criteri, revel comprle, if not slightly more fvourle, survivl rtes for oth mterils. 10 The differences in longevity results etween the vrious forms of study my e ccounted for y numer of fctors. These include: Opertor skill: Opdm et l 2010, 10 hve reported comprle nnul filure rtes of mlgm (1.3%) nd resin composite restortions (1.8%) mongst ptients with low predisposition towrds dentl cries t 5-yer follow-up. Interestingly, t 12 yers the nnul filure rte for resin composite ws lower (1.7%) versus 2.4% for silver mlgm restortions. It ws concluded tht opertor skill ws key determinnt for success when plcing resin composite restortions. Mterils nd techniques used. Cvity size nd the criteri for plcement. Ptient complince with orl hygiene dvice, the orl environment nd its contriution to ptient's susceptiility to cries. 10 The mens y which the tretment my e funded. 12 Polymeriztion shrinkge Polymeriztion shrinkge is key fctor, ccounting for the reltive filure of direct posterior resin composite restortions. A mjority of the currently ville products contin the monomer isphenol-a glycidyl methcrylte (is- GMA). The ltter is ulky monomer; hence upon polymeriztion the distnce etween the monomers decreses significntly, resulting in volumetric shrinkge. Reports from severl studies hve descried volumetric polymeriztion shrinkge of resin composites to rnge from etween 2 to 3%. 13 Cliniclly, s the mteril is plced within ounded cvity wlls, the process of shrinkge hs the tendency to trnsfer stresses to the cvity wlls, which my result in the shering of the dhesive interfce etween the restortive mteril nd tooth, or indeed the pulling 722 DentlUpdte Octoer 2015

3 of opposing wlls towrds ech other. The ltter could mnifest cliniclly in the formtion of mrginl gp, tooth structure deformtion cuspl contrction / frcture, post-opertive sensitivity (POS), recurrent cries, enmel crcks or mrginl stining. As listed in Tle 1, the ltter re often the primry resons for oserving clinicl filures with direct posterior resin composite restortions. The risk of POS hs een reported to e more likely to occur in ssocition with lrger, more complex restortions. However, for the mjority of ptients, POS disppers over period of time from plcement. 14 A longevity study y Mjör 1997, 15 where 537 posterior composite restortions were plced y generl prctitioners, reported medin survivl time of 6 yers. The primry cuse of filure ws descried to e recurrent cries, ccounting for 38% of ll overll filures. Kopperud et l hve reported 2.5 times greter risk of filure of resin composite restortions for ptients who present with higher cries predisposition. Polymeriztion shrinkge occurring t the gingivl mrgin is prime site for the stgntion nd ingress of criogenic cteri. A numer of fctors cn influence the mgnitude of contrction, some of these re under the control of the dentl opertor. Resin composites with high modulus of elsticity re ssocited with greter stress trnsference to the tooth structure upon polymeriztion s the elstic modulus of composite resin tends to increse with the reltive filler content. On the other hnd, more highly filled resins re likely to disply lesser levels of polymeriztion shrinkge s result of their lower reltive resin content. The technique of ppliction is lso importnt. The incrementl insertion of resin composites reduces the ulk of mteril cured t ny one point in time, therey decresing the effect of the setting rection. Incrementl ppliction lso reduces the so-clled C-fctor (which is the rtio of the onded re of the restortion to tht of the unonded re). A reduction in the C-fctor is thought to relieve the stresses developed t the dhesive lyer etween the tooth nd resin mteril. 17 Other ttempts to reduce the volume of shrinkge include the Figure 5. Cse 2: Restortion removl. Figure 6. Cse 2: Sectionl mtrix nd plcement nd SDR lining. ppliction of ses/liners with lower elstic moduli, such s glss ionomer cements (including those of the resin-modified vriety), chemiclly cured resin composite formultions, the use of contemporry low shrinkge, ulk-fill mterils nd perhps, less frequently tody, the inclusion of etqurtz inserts such s Cern, Nordisk, Sweden. 18 The prescription of indirect resin composite restortions will lso lrgely negte the effect of polymeriztion shrinkge, s the ulk of this tkes plce extr-orlly. Clerly, opertor knowledge nd skill re prmount towrds successful outcome. The im of this pper is to descrie, on cse y cse sis, the differing methods of resin composite ppliction for the restortion of posterior cvities, some of the techniques for which Figure 7. Cse 2: Completed restortion with Tetric Bulk Fill. Figure 8. (, ) Cse 3: Pre-opertive sitution. my prove to e more workle for given opertor thn nother, together with n overview of the pros nd cons of ech technique descried, supported where possile y evidence-sed dt. The techniques will lso highlight dvnces which hve tken plce in resin technology nd n incresed understnding of the properties nd ehviour of this mteril, such s the use of ulk-fill mterils, direct-indirect plcement techniques nd the use of indirect resin composite restortions, which my hve the potentil to improve the longer term outlook of these Octoer 2015 DentlUpdte 725

4 c Figure 9. ( d) Cse 3: To show isoltion, onding protocol nd post-opertive sitution. restortions, together with some of the commonly encountered pitflls ssocited with the use of this mteril in this ppliction. The cses descried elow were completed s prt of the in course ssessment requirements for the MSc in Aesthetic Dentistry, King s College London. The direct plcement of posterior resin composite restortion The direct plcement of resin composite is perhps the most commonly pplied method for the prescription of the ltter form of restortive mteril. It provides mens of delivering conservtive, esthetic, onded restortions with the merits of lower reltive cost (s no lortory fees or dditionl mterils for indirect restortions re required), offers single visit procedure nd the voidnce of d provisionl restortion, which would present the dded compliction of microlekge. However, plcement protocols my e highly demnding of opertor skill for the ttinment of superior esthetic outcome nd morphology (tht is conducive towrds optiml function), oth in terms of occlusl ntomy nd the ttinment of ptent, redily clensle inter-proximl contct re(s), prticulrly for more complex cvity designs nd functionlly demnding cses. Adequte moisture control my lso e prolemtic which, if suoptiml, my culminte in premture filure of n dhesively retined restortion. Improper resin plcement technique my lso compound the welldocumented concern of polymeriztion shrinkge, nd the ssocited sequele s discussed ove. Cse 1: Directly onded resin composite restortion Cse 1 (Figures 1, 2, 3) is n exmple of 30-yer-old mle who presented s new ptient dignosed with multiple crious lesions, including tht ffecting the upper left first molr. The ptient ws prescried trditionl direct conservtive composite resin restortions for the mngement of the forementioned crious lesions. When employing trditionl direct composite resin s posterior restortive, it is recommended tht n incrementl lyering technique e dopted using increments no lrger thn 2 mm, with the im of reducing polymeriztion shrinkge stress nd llowing sufficient light penetrtion through the mteril itself. 19 Vrious mens of incrementl ppliction hve een descried in the literture, such s the olique lyering concept nd the horizontl lyering concept. Following dministrtion of locl nesthesi, occlusl stops were mrked using rticulting pper (GHM 12 Micron Foil Hnel, Coltene Whledent Inc, Ohio, USA) nd the qudrnt isolted using ruer dm (Roeko Non Ltex FlexiDm, Coltene Whledent Inc, Ohio, USA) nd dentl cries susequently removed (Figure 2). The ltter culminted in the minor involvement of the mesil mrginl ridge nd contct re of the first molr tooth, thus it ws decided to restore this tooth vi tunnel preprtion in order to preserve the well-developed mrginl ridge. A cellulose cette strip ws pplied nd susequently secured with wooden wedge tht ws used to sel the rech during restortion. Increments of micro hyrid posterior composite, (Filtek P60, A3, 3M ESPE, Loughorough, UK) were redied nd mintined in light-proof continer. The cvities were conditioned using totl etch technique (37% phosphoric cid) followed y dentine onding gent (Prime & Bond NT, Dentsply, USA) tht ws ir dispersed for 5 seconds (so s to permit solvent evportion) nd cured for 10 seconds (Coltolux LED, Coltene Whledent Inc, Ohio, USA). The first increment ws dpted to the floor of the cvity nd cured for 40 seconds. Susequent increments were lyered on lternting cvity wlls nd cured for 40 seconds until the cvity 726 DentlUpdte Octoer 2015

5 reched occlusl level where smller increments were then used to recrete the cuspl ntomy. Brown fissure tints (Color, Kerr CA, USA) were pplied into the centrl fissures nd lightly rushed nd dispersed using micro rush nd cured for 20 seconds. Following ruer dm removl, the restortion ws mrked in oth sttic nd dynmic occlusl positions using rticulting pper. A green stone (Dur-Green, Shofu, Jpn) in friction grip ws used to djust the occlusion to conform to the pre-opertive occlusl prescription. Mrginl refinement nd smoothing were chieved using white stone (Dur-White, Shofu Jpn) in ltch grip, followed y dry high lustre polishing, performed fter further 3 dys, to permit drk polymeriztion using dimond impregnted rotry rush (Astrorush, Ivoclr Vivdent, Schn, Liechtenstein). Restortions were post-cured for 40 seconds, following the ppliction of glycerine, so s to permit polymeriztion of the surfce lyer, which my e ffected y the concept of oxygen inhiition, wherey the presence of mient oxygen will prohiit complete polymeriztion of the surfce lyer nd the presence of medium such s glycerine will serve to lock the ltter nd therey permit polymeriztion upon further light curing. Figure 3 provides view of the definitive restortion. Cse 2: Use of ulk-fill mterils As n ttempt to overcome the mtter of polymeriztion shrinkge nd the ssocited sequele, ulk-fill resins were introduced to the mrket plce. Such mterils hve shown the potentil in vitro to demonstrte reduced polymeriztion shrinkge stress vlues, 20,21,22 s well s incresed depth of cure, 23 when compred to their predecessors. A ulk-fill resin, such s SDR, does not vry sustntilly from its counterprts in terms of generl composition nd filler lod, ut hs its effect through lrger monomer with n emedded modultor tht medites polymeriztion, providing conformtionl flexiility during cross-link formtion nd less polymeriztion stress. 24 Incresing the trnslucency of the mteril itself lso llows for greter light penetrtion nd Figure 10. ( d) Cse 3: To show mster impression, working die nd completed l fricted composite inly. Figure 11. (, ) Cse 4: Cvity preprtion nd sectionl impression in lginte. susequent depth of cure. 23,25 Alterntive photo-inititor systems hve lso een utilized tht initite more potent degree nd depth of conversion due to n intensive sorption of light nd high photorectivity. 26 Silornes represent nother group of composite resin tht hve een shown to demonstrte consistently low polymeriztion shrinkge vlues elow 1%, y dopting unique ring opening polymeriztion through the use of new siloxne-oxirne sed monomer. 27 The use of such resin is depicted y Cse 2 (Figures 4 7) tht c d demonstrtes the replcement of defective mesio-occlusl glss ionomer restortion on n upper left first permnent molr of femle ptient in her mid 20s (Figure 4). In this cse, the sme protocol ws followed for pre-opertive ssessment nd onding s would e for trditionlly lyered composite restortion (Cse 1). In this instnce, the first increment of flowle ulk-fill mteril (SDR, Dentsply, USA) ws plced t the floor of the cvity nd proximl ox in lyer of 2 3 mm nd cured for 20 seconds (Figure 6). The occlusl surfce nd mjority of the proximl 728 DentlUpdte Octoer 2015

6 c d e Figure 12. ( e) Cse 4: Chirside friction of semi-direct composite inly on silicone working die. surfce were then restored using Tetric EvoCerm Bulk Fill IVA (Ivoclr Vivdent, Schn Liechtenstein) (Figure 7) plced in two increments pproximtely 3 mm in thickness. Although the mnufcturers of these two mterils recommend curing time of 20 seconds t depth of 4 mm, slightly smller increments were used in this instnce nd cured for 30 seconds, with finl cure of 20 seconds from ech surfce of the restortion. Such methods were dopted to help reduce polymeriztion shrinkge stress nd prevent ny uncured resin within the restortion. Erly results (12 36 months) from the use of Silorne, SDR nd Kerr Sonic Fill in posterior cvities seem to demonstrte comprle survivl rtes to trditionl composite resin, ssuming strict onding protocols re followed. 28,29,30 Cse 3: Indirect resin composite restortion As discussed ove, the direct plcement of posterior resin composite restortions is highly demnding of opertor skill. Furthermore, the ttinment of ptent inter-proximl contcts nd ulk frcture nd the consequences of polymeriztion shrinkge re commonly cited prolems with this technique. The plcement of resin composite restortions my lso tke more clinicl time s opposed to n nlogous silver mlgm restortion owing to the higher level of technique sensitivity. The ltter my prove to e chllenging for some ptients. The indirect friction of resin composite restortions offers the potentil to overcome some of the prolems descried ove, s restortions my e fricted extr-orlly without the chllenges of the soft tissues, slivry contmintion nd ptient co-opertion. Contct re nd occlusl ntomy nd form, respectively, cn e developed on die stones, with the use of n pproprite form of occlusl pprtus if deemed necessry. As polymeriztion shrinkge tkes plce extr-orlly, the consequences re reduced (other thn dimensionl chnges occurring t the level of the resin lute). Furthermore, there is the potentil to extend the level of polymeriztion eyond light curing, which hs een climed to enhnce the mechnicl properties of the restortion, s well s offer more fvourle prognosis in situtions where cvity mrgins rest within dentine. A review of direct nd indirect restortions y Mnhrt et l 31 hs determined nnul filure rtes of indirect composite inlys to e 1.9% (1.7% nd 1.4% for cermic nd gold indirect restortions, respectively). This review lso showed tht indirect restortions demonstrted significntly lower nnul filure rtes thn direct restortions fricted using erlier mterils. Figures 8 10 demonstrte n exmple of n indirect resin inly restortion (Cse 3), prescried to replce directly onded resin restortion, presenting with n open contct nd mrginl defect (Figure 8). The tretment ojectives were to reduce symptoms of food trpping nd the potentil for secondry cries y estlishing tight inter-proximl contct with stisfctory peripherl mrginl sel. An indirect lortory mde composite inly (Grdi Indirect, GC Corportion, Tokyo, Jpn) ws prescried s the prepred cvity extended eneth the gingivl mrgin nd pst the emrsures, which would render seling the floor of the cvity nd simultneously providing n optiml contct point unpredictle. Figure 9 demonstrtes delivery of the finl restortion tht ws onded using selfdhesive dul cure resin cement (RelyX Unicem, 3M ESPE, UK). The indirect technique s shown y Cse 3 does, however, require the locking out of hrd tissue undercuts. There Octoer 2015 DentlUpdte 729

7 c Figure 13. ( c) Cse 4: Pre- nd post-opertive views nd demonstrtion of occlusion. is lso need to provide provisionl restortion, record impressions, dditionl visits nd lortory costs (Figure 10). Cse 4: Direct/Indirect technique As mens of overcoming the need for some of the ove spects, there is the potentil to fricte the restortion using direct-indirect pproch. This is shown y Figures 11 13, which is n exmple of the ppliction of Direct/ Indirect technique using silicone die fricted chirside to provide toothcoloured restortion of lrge cvity tht hs less potentil for polymeriztion shrinkge stress compred to directly plced composite restortion nd cn e completed in-office. Thordrup et l 32 hs reported n 80% survivl rte for semi-direct inlys t 10 yers tht proved to e comprle to indirect composite, direct nd indirect cermic inlys. Vn Dijken 33 hs lso reported tht the time nd expense of Clss II indirect composite restortion plcement my not e justified s he reported comprle longevity t 11 yers of semidirect Clss II composite inlys. Preprtion egn with dministrtion of locl nesthetic nd removl of the previous restortion. Minor undercuts were eliminted nd internl line ngles softened. The inly preprtion ws kept to the depth of the previous restortion nd ws smoothed with white stone nd ruer polishing point. Non-impregnted retrction cord ws used to open the mesil gingivl mrgin of the preprtion (Figure 11) redy for n impression tht ws mde using lginte in sectionl stock try coted with dhesive (Figure 11). If this technique were to e employed in more complicted sitution, for exmple n only, it would e sensile to record n opposing impression for ccurte rticultion. The use of PVS-sed mterils would lso offer higher level of ccurcy s opposed to the use of lginte, which is less dimensionlly stle. The working die ws fricted using silicone die mteril (Mch II, Prkell Inc, NY, USA). This ws extruded into the impression to replicte the dentl hrd nd soft tissues. A silicone ite registrtion pste (Blue Mousse, Prkell Inc, NY, USA) ws then pplied to plstic se former nd to the remining prt of the impression. The se former ws then ttched to the impression nd llowed to set, following which it is simply removed from the impression to form n immedite working die (Figure 12). The die ws prtilly sectioned to llow ccess to the mesil contct point of the preprtion. A sectionl mtrix foil (Plodent, Dentsply, USA) ws secured in plce with temporry filling mteril (Coltosol, Coltene Whledent Inc, USA) in order to recrete the mrginl ridge nd interproximl contct point using stock direct posterior composite resin mteril (Filtek P60, 3M ESPE, UK) (Figure 12). The 730 DentlUpdte Octoer 2015

8 Technique Advntges Disdvntges Direct plcement No lortory fee Completed in single visit No provisionl restortion required Highly conservtive Mterils nd equipment redily ville in stndrd dentl office set-up Vst vriety of shdes nd trnslucencies Cretion of tight nd well contoured interproximl contct cn e difficult Creful onding nd lyering protocols re technique sensitive nd time consuming Isoltion nd moisture control must e mintined throughout whole procedure Greter polymeriztion shrinkge stress Highly esthetic outcomes require skilled opertor Direct plcement with ulk-fill resins No lortory fee Completed in single visit No provisionl restortion required Highly conservtive More time efficient to plce Lower polymeriztion shrinkge stress Greter depth of cure Restricted vriety of shdes nd trnslucencies Cretion of tight nd well contoured interproximl contct cn e difficult Requires creful onding protocols Isoltion nd moisture control must e mintined throughout whole procedure My e more expensive thn trditionl composite nd not prt of core stock lists Highly esthetic outcomes require skilled opertor Indirect plcement Potentil to enhnce mechnicl properties through extensive 3-dimensionl light curing nd het tretment A pre-cured restortion elimintes prolems ssocited with polymeriztion shrinkge stress More precise control of ntomy nd occlusion Isoltion only required for finl onding of inly Precise mrginl fit nd dption Aesthetics controlled y skilled technicin More predictle mrginl stility in dentine Lortory fees incurred Requires two clinicl visits Impressions required Requires provisionl restortion Requires removl of undercuts Semi-direct plcement No lortory fee Cn e completed on sme dy No provisionl restortion required Allows extensive 3-dimensionl light curing A pre-cured restortion elimintes prolems ssocited with polymeriztion shrinkge stress Isoltion only required for finl onding of inly Works with ny dentl composite system Additionl time must e llocted for inly friction nd fitting Impressions required Requires removl of undercuts Requires dditionl mterils nd equipment (die mteril, se former) Highly esthetic outcomes require skilled opertor Tle 2. A summry of the dvntges nd disdvntges of the vrious techniques tht my e used when prescriing resin composite restortions. inly ws then uilt up in cuspl increments nd rown tints pplied to the centrl fissures (Color +, Kerr, CA, USA) (Figure 12c). Curing of ech increment ws crried out for 10 seconds followed y close curing of the restortion off the die for 1 minute over ech surfce (Coltolux LED, Coltene Whledent Inc, USA). The die ws then fully sectioned to refine the restortion fit mrgins using fine rsive disc (Soflex, 3M ESPE, UK). Finl polishing ws crried out with dimond impregnted rotry rush (Astrorush, Ivoclr Vivdent, Lichtenstein) (Figure 12d, e). The ptient returned on the sme dy for delivery of the restortion (Figure 13). A onding nd finishing protocol identicl to tht of l fricted direct inly (Cse 3) ws followed. Occlusl djustments were mde intr-orlly s would e similr to direct restortion (Cse 1) (Figure 13). The finl restortion (Figure 13c) ws ccepted well nd tight interproximl contct ws confirmed with floss. Current clinicl dt for such technique hs shown 84% of semi direct composite inlys hving gp free mrgins t 5 yers, demonstrting good mrginl integrity. 34 This technique my help reduce cervicl mrginl lekge compred to direct technique tht cn mke it suitle for high cries risk ptients where the cervicl mrgin of the cvity is locted within dentine. 34 Conclusion In summry, resin composite my offer the clinicin vile lterntive Octoer 2015 DentlUpdte 733

9 to silver mlgm for the restortion of posterior defects. It is impertive for the opertor to understnd the enefits offered y the use of this mteril. Hving sound knowledge of differing plcement techniques my ssist the clinicin with more chllenging clinicl scenrios. Tle 2 provides summry of the vrious techniques tht my e used when prescriing tooth-coloured resin composite restortions. References 1. Hickel R, Mnhrt J, Grci-Godoy F. Clinicl results nd new developments of direct posterior restortions. Am J Dent 2000; 13: 41D 54D. 2. Ginsford ID, Dunne SM. Silver Amlgm in Clinicl Prctice 3rd edn. Bristol: Wright (Dentl Hndooks), United Ntions Environmentl Progrmme. Minmt Convention greed y ntions. UNEP, Online rticle ville t: spx?document ID= 2702 ArticleD = 9373 (June 2013). 4. Austrlin Government: Ntionl Helth nd Medicl Reserch Council. Dentl Amlgm nd Mercury in Dentistry. A Report of NHMRC Working Prty, Mrch Aville t 5. Lynch CD, Wilson NHF. Mnging the phsedown of mlgm: prt II. Implictions for prcticing rrngements nd lessons from Norwy. Br Dent J 2013; 215: Opdm N, Bronkhorst E, Roeters J, Loomns B. A retrospective clinicl study on the longevity of posterior composite nd mlgm restortions. Dent Mter 2007; 23: Burke F, Mckenzie L, Snds P. Dentl mterils wht goes where? Clss I nd Clss II cvities. Dent Updte 2013; 40: Corre M, Peres M, Peres K, Hort B, Brros A, Demrco F. Amlgm or composite resin? Fctors influencing the choice of restortive mteril. J Dent 2012; 40: Rj V, Mcedo G, Ritter A. Longevity of posterior composite restortions. J Esthet Rest Dent 2007; 19: Opdm N, Bronkhorst E, Loomns B, Huysmns M. 12 Yer survivl of composite vs mlgm restortions. J Dent Res 2010; 89: Mjör I, Moorhed J, Dhl J. Resons for replcement of restortions in permnent teeth in generl dentl prctice. Int Dent J 2000; 50: Türkün LS, Aktener BO, Ateş M. Clinicl evlution of different posterior resin composite mterils: 7-yer report. Quintessence Int 2003; 34: Burgess JO, Wlker R, Dvidson JM. Posterior resin-sed composites: review of the literture. Peditr Dent 2002; 24: Briso AL, Mestrener SR, Delicio G et l. Clinicl ssessment of postopertive sensitivity in posterior composite restortions. Oper Dent 2007; 32(5): Mjör I. The resons for replcement nd the ge of filed restortions in generl dentl prctice. Act Odontol Scnd 1997; 55: Kopperud S, Tveit A, Grden T, Sndvik L, Espelid I. Longevity of posterior dentl restortions nd resons for filure. Eur J Orl Sci 2012; 120: Versluis A, Tntirjoin D, Dougls W. Do dentl composites lwys shrink towrds the light? J Dent Res 1998; 77: Millr B, Roinson P. Eight yer results with direct cermic restortions (Cern). Br Dent J 2006; 21: Kwon Y, Ferrcne J, Lee IB. Effect of lyering methods, composite type, nd flowle liner on the polymeriztion shrinkge stress of light cured composites. Dent Mter 2012; 28(7): doi: /j. dentl Epu 2012 My Rullmnn I, Schttenerg A, Mrx M, Willershusen B, Ernst CP. Photoelstic determintion of polymeriztion shrinkge stress in low-shrinkge resin composites. Schweiz Montsschr Zhnmed 2012; 4: Burgess J, Ckir D. Comprtive properties of low-shrinkge composite resins. Compend Contin Educ Dent 2010 My; 2: Ilie N, Hickel R. Investigtions on methcrylte-sed flowle composite sed on the technology. Dent Mter 2011 Apr; 4: Flury S, Hyoz S, Peutzfeldt A, Hüsler J, Lussi A. Depth of cure of resin composites: is the ISO 4049 method suitle for ulk fill mterils? Dent Mter 2012; 28: Dentsply DeTrey GmH. Scientific Compendium SDR My; (2.2): Lssil LV1, Ngs E, Vllittu PK, Groushi S. Trnslucency of flowle ulk-filling composites of vrious thicknesses. Chin J Dent Res 2012; 15: Ivoclr Vivdent AG Reserch nd Development. Tetric EvoCerm Bulk Fill Scientific Documenttion 2013; 2.3: Weinmnn W, Thlcker C, Guggenerger R. Silornes in dentl composites. Dent Mter 2005; 21: Vn Dijken JWV, Pllesen U. 2012; SDR, Xeno V+, Cerm X mono+ Clinicl Study, Results t 12 months (Dt ville from Dentsply DeTrey). 29. Frnkenerger R, Schulz M, Holl S, Seitner T, Mtthis J, Roggendorf MJ. Bulk-fill vs. lyered resin composite restortions in Clss II cvities: six-month results. Deprtment of Opertive Dentistry nd Endodontics, Medicl Center for Dentistry, University Medicl Center Giessen nd Mrurg, Cmpus Mrurg, Georg-Voigt-Str. 3, D Mrurg, Germny. 30. Brcco B, Perdigão J, Crer E, Cellos L. Two-yer clinicl performnce of low-shrinkge composite in posterior restortions. Oper Dent 2013; 38: Mnhrt J, Chen H, Hmm G, Hickel R. Buonocore Memoril Lecture. Review of the clinicl survivl of direct nd indirect restortions in posterior teeth of the permnent dentition. Oper Dent 2004; 29(5): Thordrup M(1), Isidor F, Hörsted-Bindslev P. A one-yer clinicl study of indirect nd direct composite nd cermic inlys. Scnd J Dent Res 1994 Jun; 102(3): Vn Dijken JMV, Hörstedt P. Mrginl rekdown of 5-yer-old direct composite inlys. J Dent 1996; 24(6): Shortll AC, Bylis RL, Bylis MA, Grundy JR. Mrginl sel comprisons etween resinonded Clss II porcelin inlys, posterior composite restortions, nd direct composite resin inlys. Int J Prosthod 1989; 2(3): Both digitl nd film enefits, together t lst. Compct, quiet, nd ffordle, the new CS 7200 is the idel spce sving solution for routine introrl exms nd chirside use with leding imge qulity (true resolution up to 17 lp/mm). For more informtion or to plce n order cll (outside UK ) emil sles.uk.csd@crestrem.com or visit Follow us on: Crestrem Dentl Ltd NEW CS DentlUpdte Octoer 2015