Thepresentreviewfollowedthesamesearchmethodologyas thepreviousone[1].
2.1.1. Focusedquestions
“Whatare the survivalandcomplicationrates of tooth-supportedFDPsafterameanobservationperiodofatleast3 years?”“Arethesurvivalandcomplicationsratesof metal-ceramicandall-ceramictooth-supportedFDPssimilarafter ameanobservationperiodofatleast3years?”
2.1.1.1. PICO. Thepopulation,intervention,comparisonand outcomes, i.e. the “PICO” for this systematic review was definedasfollows:
Population:Subjectswithanteriorand\orposterior tooth-supportedfixeddentalprostheses[FDP].
Intervention:All-ceramicFDPs Comparison:Metal-ceramicFDPs
Outcomes:Clinicalsurvivalrates,andtechnicaland\or bio-logicalcomplicationrates.
AliteraturesearchindatabasesPubMed,Embase,Cochrane Central RegisterofControlledTrials (CENTRAL) search was performed.Thesearchwaslimitedtohumanstudiesindental journalswritteninEnglishlanguage.Articlespublishedfrom 1stofDecember2006uptoandincludingthe31stofDecember 2013wereincluded.Thefollowingdetailedsearchtermswere usedandthesearchstrategywasasfollows:
P and I: crowns[MeSH] OR crown[MeSH] OR dental crowns[MeSH]ORcrowns,dental[MeSH]ORDenture,Partial, Fixed[Mesh])) OR (crown*[all fields] OR fixed partial den-ture*[allfields]ORFPD[allfields]ORFPDs[allfields]ORfixed dental prosthesis[all fields] OR fixed dental prostheses[all fields] OR FDP[all fields] OR FDPs[all fields] OR bridge*[all fields].
C: Ceramic[MeSH] OR ceramics[MeSH] OR metal ceramic restorations[MeSH])) OR (ceramic*[All Fields] OR all-ceramic[all fields] OR Dental Porcelain[All Fields] OR metal-ceramic[AllFields].
O:Survival[Mesh]ORsurvivalrate[Mesh]ORsurvival anal-ysis[Mesh]ORdentalrestorationfailure[Mesh]ORprosthesis failure[Mesh]ORtreatmentfailure[Mesh].
Thecombinationinthebuilderwassetas“P&IANDC ANDO”.
The electronic search was complemented by manual searches of the bibliographies of all full text articles and related reviews, selected from the electronic search. The search wasindependently performedbytworesearches(IS and NAM). Any disagreement was resolved in consensus betweentheauthors.
Uptothelevelofdataextraction,theliteraturewas evalu-atedforbothsinglecrownsandmultiple-unitFDPsatthesame time.Atfulltextlevelthemanuscriptsweresplitaccordingto thereconstructiontype.
606
dental materials 31 (2015)603–6232.2. Inclusioncriteria
BesidesthementionedRCTs,thissystematicreviewwasbased onprospectiveorretrospectivecohortstudies,orcaseseries.
Theadditionalinclusioncriteriaforstudyselectionwere:
• Studieswithaminimummeanfollow-upperiodof3years.
• Included patients had been examined clinically at the follow-upvisits,i.e.publicationsbasedonpatientrecords only,onquestionnairesorinterviewswereexcluded.
• Studiesreporteddetailsonthecharacteristicsofthe recons-tructions,onmaterialsandmethodsandontheresults.
• Studieshadtoincludeandfollow-upatleast10patients.
• Publicationswhichcombinedfindingsoftoothandimplant supportedreconstructions whereatleast90% was tooth supportedreconstructions.
Thefinal selectionbasedon inclusion/exclusioncriteria wasmadeforthefulltextarticles.ForthispurposeSections 2–4ofthesestudieswerescreened.Thisstepwasagain car-riedoutbytworeaders(IS,NAM)anddouble-checked.Any questionsthatcameupduringthescreeningwerediscussed toaimforconsensus.
2.3. Exclusioncriteria
Thefollowingstudytypeswereexcluded:
• invitrooranimalstudies;
• studieswithlessthan3yearsoffollow-up;and
• studiesbasedonchartreviewsorinterviews.
2.4. Selectionofstudies
Titles and abstracts of the searches were independently screenedbytworeviewers(IS&NAM)forpossibleinclusionin thereview.Furthermore,thefulltextofallstudiesofpossible relevancewasthenobtainedandsplitintoliteratureonsingle crowns(part1ofthereview)andliteratureonmultiple-unit FDPs(part2ofthereview).
The literature on single crowns was independently assessedbythreeofthereviewers(IS,BEP&NAM).Any dis-agreementregardinginclusionwasresolvedbydiscussion.
2.5. Dataextraction
Dataonthefollowingparameterswereextracted:author(s), yearofpublication,studydesign,plannednumberofpatients, actualnumberofpatientsatendofstudy,drop-outrate,mean age,agerange, operators,materialframework, brandname offramework material,veneering material, brand name of veneeringmaterial,typeofmanufacturingprocedure, num-berofFDPs,numberofabutmentteeth,numberof(non)vital abutment teeth, number ofpontics, location ofFDP (ante-rior,posterior,maxilla,mandible),reportedmeanfollow-up, follow-up range, published FDP survival rate, number of FDPslost (anterior,posterior),reportedbiological complica-tions (caries, periodontal, rootfracture), reported technical complications (framework fracture, minor chipping, major chipping,lossofretention),estheticcomplications(marginal
discoloration),reportednumberofpatientsfreeof complica-tions.Basedontheincludedstudies,theFDPsurvivalratewas calculated.Inaddition,thenumberofeventsforalltechnical, biologicalandestheticcomplicationswasextractedandthe correspondingtotalexposuretimeofthereconstructionwas calculated.
Datawasextractedindependentlybytworeviewers(IS&
NAM)usingadataextractionform.Disagreementregarding dataextractionwasresolvedbyconsensusofthreereviewers (IS,BEP&NAM).
2.6. Statisticalanalysis
Forthestatisticalanalysisthenewdataofthepresentreview, encompassingthe33studieswascombinedwiththeprevious dataofthe34studiespublishedinPjeturssonetal.,2007.
Hence,thedataincludedinthepresentanalysiswas pub-lishedfrom1990untiltheendof2013.
SurvivalwasdefinedastheFDPremaininginsituwithor withoutmodificationfortheobservationperiod.
Failureand complicationrateswere calculatedby divid-ing the numberofevents(failuresor complications)inthe numeratorbythetotalFDPexposuretimeinthedenominator.
Thenumeratorcouldusuallybeextracteddirectlyfromthe publication.Thetotalexposuretimewascalculatedbytaking thesumof:
(1) ExposuretimeofFDPsthatcouldbefollowedforthewhole observationtime.
(2) ExposuretimeuptoafailureoftheFDPsthatwerelost duetofailureduringtheobservationtime.
(3) Exposure time up to the end of observation time for FDPsthat didnotcomplete the observationperioddue to reasons such as death, change of address, refusal to participate, non-response, chronic illnesses, missed appointmentsandworkcommitments.
Foreachstudy,eventratesfortheFDPswerecalculatedby dividingthetotalnumberofeventsbythetotalFDPexposure timeinyears.Forfurtheranalysis,thetotalnumberofevents wasconsideredtobePoissondistributedforagivensumof FDPexposureyearsandPoissonregressionwithalogarithmic link-functionandtotalexposuretimeperstudyasanoffset variablewereused[6].
Robuststandarderrorswerecalculatedtoobtain95% con-fidence intervals of the summary estimates of the event rates. To assess heterogeneity of the study specific event rates,theSpearmangoodness-of-fitstatisticsandassociated p-valuewere calculated.If the goodness-of-fit p-value was below0.05fiveyearsurvivalproportionswerecalculatedvia therelationshipbetweeneventrateandsurvivalfunctionS, S(T)=exp(−T*eventrate),byassumingconstant eventrates [7].The95%confidenceintervalsforthesurvivalproportions werecalculatedbyusingthe95%confidencelimitsoftheevent rates.MultivariablePoissonregressionwasusedtoformally compare construction subtypes and to assess other study characteristics.AllanalyseswereperformedusingStata®, ver-sion13.1.
dentalmaterials31(2015)603–623
607
Table1–Studyandpatientcharacteristicsofthereviewedstudiesforall-ceramiccrowns.
Study Yearof
publication
Core material
Study design
No.of patientsin
study
Agerange Meanage Setting Drop-out(in
percent)
Gehrtetal. 2013 Lithiumdisilicate
glassceramic
Prospective 41 34 n.r. University 10%
Monacoetal. 2013 Denselysintered
zirconia
Retrosp. 398 48.6 18–84 Privatepractice 0%
Passiaetal. 2013 Denselysintered
zirconia
RCT 123 42.7 24–73 University 37%
Rinkeetal. 2013 Denselysintered
zirconia
Prosp. 53 49.6 29–70 Privatepractice 8%
Sagitkayaetal. 2012 Denselysintered
zirconia
RCT 42 n.r. n.r. University 0%
Sorrentinoetal. 2012 Denselysintered
alumina
Retrosp. 112 n.r. 18–69 University 1%
Ortorpetal. 2012 Denselysintered
zirconia
Retrosp. 169 n.r. n.r. Privatepractice 32%
Vigolo&Mutinelli 2012 Denselysintered
zirconia
Prosp. 20 32 19–55 Privatepractice 3%
Wollebetal. 2012 Leucitreinforced
glassceramic
Retrosp. 52 61.3 34–84 University 14%
Cortellini&Canale 2012 Lithium-disilicate
glassceramic
Prospective 76 36 20–61 Privatepractice 0%
Beieretal. 2012
Feldspathic/silica-based ceramic
Retrosp. 302 46.5 n.r. University 0%
Rinkeetal. 2011 Glass-infiltrated
alumina
Retrosp. 80 n.r. n.r. Privatepractice 0%
Cehrelietal. 2011
Feldspathic/silica-basedceramic Glass-infiltrated alumina
RCT 33 n.r. n.r. University 0%
Kokuboetal. 2011 Glass-infiltrated
alumina
Prospective 39 50.9 n.r. Privatepractice 13%
Beueretal. 2010 Denselysintered
zirconia
Prospective 38 50.9 27–71 University 0%
Schmittetal. 2010 Denselysintered
zirconia
Prosp. 10 42.1 n.r. University 10%
Vanoorbeeketal. 2010 Denselysintered
alumina
Prosp. 130 N.r. 18–70 University 27%
Kokuboetal. 2009 Denselysintered
alumina
Prospective 57 46.4 20–70 University 19%
Valenti&Valenti 2009 Lithiumdisilicate
glassceramic
Retrosp. 146 n.r. n.r. Privatepractice 1%
Signoreetal. 2009 Lithiumdisilicate
glassceramic
Retrosp. 200 37.6 19–66 University 4%
608
dentalmaterials31(2015)603–623 Table1(Continued)Study Yearof
publication
Core material
Study design
No.of patientsin
study
Agerange Meanage Setting Drop-out(in
percent)
Toksavul&Toman 2007 Lithiumdisilicate
glassceramic
Prospective 21 38.3 18–60 University 0%
Burke 2007
Feldspathic/silica-based ceramic
Prospective 16 37.5 22–51 University 17%
Malamentetal. 2006*
2001
Glass-infiltrated alumina Feldspathic/silica-basedceramic Leucitreinforced glassceramic
Prospective n.r. n.r. n.r. Privatepractice n.r.
Galindoetal. 2006 Denselysintered
alumina
Prospective 50 22–75 n.r. University 22%
Naertetal. 2005 Denselysintered
alumina
Prospective 165 17–75 57 University 27%
Walterelal. 2005 Denselysintered
alumina
Prospective 70 n.r. 38.8 University 6%
Marquardt&Strub 2006 Lithiumdisilicate reinforcedglass ceramic
Prospective 43 22–65 39.9 University 0%
Bindl&Mörmann 2004 Glass-infiltrated
alumina Feldspathic/silica-based
ceramic
Prospective 29 30–77 53 University 17%
Fradeani&Redemagni 2002 Leucitreinforced glassceramic
Retrospective 59 18–68 41 Privatepractice 8%
Bindl&Mörmann 2002 Glass-infiltrated
alumina
Prospective 21 n.r. n.r. University n.r.
Fradeanietal. 2002 Glass-infiltrated
alumina
Retrospective 13 n.r. 48 Privatepractice n.r.
vanDijkenetal. 2001 Leucitreinforced
glassceramic
Prospective 110 26–81 53 University 0%
Scherreretal. 2001
Feldspathic/silica-basedceramic Glass-infiltrated alumina
Prospective 95 n.r. n.r. University 14%
Segal 2001 Glass-infiltrated
alumina
Retrospective 253 n.r. n.r. Privatepractice n.r.
Ödmannetal. 2001 Denselysintered
alumina
Prospective 50 19–79 53 Privatepractice 18%
McLaren&White 2000 Glass-infiltrated
alumina
Prospective 107 n.r. n.r. Privatepractice 10%
dentalmaterials31(2015)603–623
609
Haseltonetal. 2000 Glass-infiltrated
alumina
Retrospective 71 18–77 47.3 University 42%
Edelhoffetal. 2000 Leucitreinforced
glassceramic
Retrospective 110 n.r. n.r. University n.r.
Erpensteinetal. 2000
Feldspathic/silica-based ceramic
Retrospective 88 n.r. 40.4 Privatepractice n.r.
Sjögrenetal. 1999
Feldspathic/silica-based ceramic
Retrospective 48 24–69 50.2 Privatepractice 40%
Sjögrenetal. 1999 Leucitreinforced
glassceramic
Retrospective 63 34–79 54.7 Privatepractice 27%
Odenetal. 1998 Denselysintered
alumina
Prospective 58 n.r. n.r. University&Privatepractice 3%
Sorensenetal. 1998 Leucitreinforced
glassceramic
Prospective 33 17–69 n.r. University 0%
Studeretal. 1998 Leucitreinforced
glassceramic
Prospective 71 n.r. n.r. University 17%
Pröbster 1997 Glass-infiltrated
alumina
Prospective 22 n.r. 42 University&Privatepractice 11%
Scottietal. 1995 Glass-infiltrated
alumina
Prospective 45 n.r. 44.2 University&Privatepractice 0%
Hüls 1995 Glass-infiltrated
alumina
Prospective 92 21–72 44.2 University 11%
Kelseyetal. 1995
Feldspathic/silica-based ceramic
Prospective n.r. n.r. >19 University 9%
Bieniek 1992
Feldspathic/silica-based ceramic
Retrospective 60 26–30 n.r. University 8%
Cheungetal. 1991
Feldspathic/silica-based ceramic
Retrospective n.r. 17–73 37.7 University 66%
n.r.standsfor“notreported”.
∗Updatefrom2006basedonpersonalcommunicationwiththeseniorauthor.