SYSTEMATIC REVIEW Failure rate of single-unit restorations on posterior vital teeth: A systematic review Kelvin I. Afrashtehfar, DDS, MSc, a Elham Emami, DDS, MSc, PhD, b Motahareh Ahmadi, DMD, MSc, c Owis Eilayyan, BSc, MSc, d Samer Abi-Nader, DMD, MSc, e and Faleh Tamimi, BDS, MSc, PhD f Restorative treatments domi- nate the dental health services provided in both private and public clinics in the majority of industrialized and developing countries. 1 Consequently, these treatments represent a signifi- cant financial burden for pa- tients and healthcare systems, especially if they fail or need to be redone, and for this reason, they require careful planning to prevent undesirable outcomes. In dental practice, some clinicians find it difficult to select the best treatment when planning to restore a defective tooth. 2-15 Treatment planning and decision making become even more complex and chal- lenging when other risk factors are involved and can influence a restoration’s longevity. This could include tooth vitality, 16 remaining tooth structure, 17,18 parafunctional habits, 19 or the presence of a removable par- tial denture. 20 Supported in part by a Knowledge Transfer Grant from the Network for Oral and Bone Health Research. a Teaching and Research Assistant, Division of Prosthodontics and Restorative Dentistry, Faculty of Dentistry, McGill University, Montreal, Quebec, Canada; Research Associate, Division of Oral Health and Society, McGill University, Montreal, Quebec, Canada; and Visiting Scholar, Department of Reconstructive Dentistry, School of Dental Medicine, University of Bern, Berne, Switzerland. b Associate Professor, Department of Restorative Dentistry, Faculty of Dentistry, University of Montreal, Montreal, Quebec, Canada. c Research Assistant, Oral Health and Rehabilitation Research Unit, Faculty of Dentistry, University of Montreal, Montreal, Quebec, Canada. d Teaching and Research Assistant, Faculty of Medicine, McGill University, Montreal, Quebec, Canada. e Division Director and Associate Professor, Division of Prosthodontics and Restorative Dentistry, Faculty of Dentistry, McGill University, Montreal, Quebec, Canada. f Associate Professor, Division of Prosthodontics and Restorative Dentistry, Faculty of Dentistry, McGill University, Montreal, Quebec, Canada. ABSTRACT Statement of problem. No knowledge synthesis exists concerning when to use a direct restoration versus a complete-coverage indirect restoration in posterior vital teeth. Purpose. The purpose of this systematic review was to identify the failure rate of conventional single-unit tooth-supported restorations in posterior permanent vital teeth as a function of remaining tooth structure. Material and methods. Four databases were searched electronically, and 8 selected journals were searched manually up to February 2015. Clinical studies of tooth-supported single-unit restorative treatments with a mean follow-up period of at least 3 years were selected. The outcome measured was the restorations’ clinical or radiological failure. Following the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines, the Cochrane Collaboration procedures for randomized control trials, the Strengthening the Reporting of Observational Studies in Epidemiology criteria for observational studies, 2 reviewers independently applied eligibility criteria, extracted data, and assessed the quality of the evidence of the included studies using the American Association of Critical Care Nurses’ system. The weighted-mean group 5-year failure rates of the restorations were reported according to the type of treatment and remaining tooth structure. A metaregression model was used to assess the correlation between the number of remaining tooth walls and the weighted-mean 5-year failure rates. Results. Five randomized controlled trials and 9 observational studies were included and their quality ranged from low to moderate. These studies included a total of 358 crowns, 4804 composite resins, and 303 582 amalgams. Data obtained from the randomized controlled trials showed that, regardless of the amount of remaining tooth structure, amalgams presented better outcomes than composite resins. Furthermore, in teeth with fewer than 2 remaining walls, high-quality observational studies demonstrated that crowns were better than amalgams. A clear inverse correlation was found between the amount of remaining tooth structure and restoration failure. Conclusions. Insufficient high-quality data are available to support one restorative treatment or material over another for the restoration of vital posterior teeth. However, the current evidence suggests that the failure rates of treatments may depend on the amount of remaining tooth structure and types of treatment. (J Prosthet Dent 2017;117:345-353) THE JOURNAL OF PROSTHETIC DENTISTRY 345
ABSTRACTStatement of problem. No knowledge synthesis exists concerning when to use a direct restorationversus a complete-coverage indirect restoration in posterior vital teeth.
Purpose. The purpose of this systematic review was to identify the failure rate of conventionalsingle-unit tooth-supported restorations in posterior permanent vital teeth as a function ofremaining tooth structure.
Material and methods. Four databases were searched electronically, and 8 selected journals weresearched manually up to February 2015. Clinical studies of tooth-supported single-unit restorativetreatments with a mean follow-up period of at least 3 years were selected. The outcome measuredwas the restorations’ clinical or radiological failure. Following the Preferred Reporting Items forSystematic reviews and Meta-Analyses guidelines, the Cochrane Collaboration procedures forrandomized control trials, the Strengthening the Reporting of Observational Studies inEpidemiology criteria for observational studies, 2 reviewers independently applied eligibilitycriteria, extracted data, and assessed the quality of the evidence of the included studies usingthe American Association of Critical Care Nurses’ system. The weighted-mean group 5-yearfailure rates of the restorations were reported according to the type of treatment and remainingtooth structure. A metaregression model was used to assess the correlation between the numberof remaining tooth walls and the weighted-mean 5-year failure rates.
Results. Five randomized controlled trials and 9 observational studies were included and theirquality ranged from low to moderate. These studies included a total of 358 crowns, 4804 compositeresins, and 303 582 amalgams. Data obtained from the randomized controlled trials showed that,regardless of the amount of remaining tooth structure, amalgams presented better outcomes thancomposite resins. Furthermore, in teeth with fewer than 2 remaining walls, high-qualityobservational studies demonstrated that crowns were better than amalgams. A clear inversecorrelation was found between the amount of remaining tooth structure and restoration failure.
Conclusions. Insufficient high-quality data are available to support one restorative treatment ormaterial over another for the restoration of vital posterior teeth. However, the current evidencesuggests that the failure rates of treatments may depend on the amount of remaining toothstructure and types of treatment. (J Prosthet Dent 2017;117:345-353)
Restorative treatments domi-nate the dental health servicesprovided in both private andpublic clinics in the majority ofindustrialized and developingcountries.1 Consequently, thesetreatments represent a signifi-cant financial burden for pa-tients and healthcare systems,especially if they fail or need tobe redone, and for this reason,they require careful planning toprevent undesirable outcomes.
In dental practice, someclinicians find it difficult toselect the best treatment whenplanning to restore a defectivetooth.2-15 Treatment planningand decision making becomeeven more complex and chal-lenging when other risk factorsare involved and can influencea restoration’s longevity. Thiscould include tooth vitality,16
remaining tooth structure,17,18
parafunctional habits,19 or thepresence of a removable par-tial denture.20
part by a Knowledge Transfer Grant from the Network for Oral and Bone Health Research.d Research Assistant, Division of Prosthodontics and Restorative Dentistry, Faculty of Dentistry, McGill University, Montreal, Quebec, Canada; Researchvision of Oral Health and Society, McGill University, Montreal, Quebec, Canada; and Visiting Scholar, Department of Reconstructive Dentistry, School ofine, University of Bern, Berne, Switzerland.ofessor, Department of Restorative Dentistry, Faculty of Dentistry, University of Montreal, Montreal, Quebec, Canada.sistant, Oral Health and Rehabilitation Research Unit, Faculty of Dentistry, University of Montreal, Montreal, Quebec, Canada.d Research Assistant, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.ctor and Associate Professor, Division of Prosthodontics and Restorative Dentistry, Faculty of Dentistry, McGill University, Montreal, Quebec, Canada.ofessor, Division of Prosthodontics and Restorative Dentistry, Faculty of Dentistry, McGill University, Montreal, Quebec, Canada.
Individual selection considering exclusioncriteria by two reviewers (abstract search)
n=3308
Abstracts selected for full-text reviewn=86
Full-text review of articles by two reviewersn=86
Full-text articles excluded by two reviewersn=54
(Not meeting the inclusion criteria = 28,inadequate data = 26)
Individual selection of final records bytwo reviewers
n=27
Studies included in the synthesisn=14
Figure 1. Preferred Reporting Items for Systematic reviews andMeta-Analyses (PRISMA) flow diagram of study selection process.
Clinical ImplicationsThe greater the amount of tooth structure, the betterthe performance of restorative materials. In posteriorvital teeth, amalgam restorations seem to performbetter than composite resin restorations, and crownsmay be preferred over direct restorations whenfewer than 2 remaining coronal walls are available.
346 Volume 117 Issue 3
In an evidence-based practice, clinicians shouldconsider their expertise, the patient’s preference andfinancial situation, and the empirical research evidence.There is a real need to attend to current research becauseprosthetic and restorative malpractice claims constitutemost dental litigation21; these claims are usually theresult of non-evidence-based, unjustified treatments, orexcessive treatments with crown prostheses rather thandirect restorations.22 However, to the best of theseauthors’ knowledge, few up-to-date, evidence-basedguidelines are available to help clinicians in this process.The purpose of this systematic review was to address thisknowledge gap by answering this research question: Isthere any difference in the failure rate of single-unitprostheses versus direct restorations in vital posteriorteeth with sufficient remaining structure?
MATERIAL AND METHODS
This systematic review was conducted according to theguidelines of the Preferred Reporting Items for Systematicreviews and Meta-Analyses (PRISMA) statement.23 Thesearch strategy was developed with the help of 2 experi-enced librarians. Articles published between January 1993and February 2015 were searched, with no languagerestriction, by using Cochrane Oral Health Group TrialsRegister, Cochrane Central Register of Controlled Trials(CENTRAL) through the Cochrane Library; MEDLINEthrough Ovid and EMBASE through Ovid (SupplementalTables 1-4). In addition, 8 selected journals and the ref-erences of all identified studies were also searchedmanually (Supplemental Table 5). We included all relevantclinical randomized controlled trials (RCTs), quasiexper-imental studies, and observational studies in which vitalposterior permanent occluding teeth (population) weretreated with either single complete crowns (intervention)or direct restorations (comparison) and followed for atleast 3 years (time) to report the failure rate (outcome).Failure was defined as any complete or partial loss of therestoration that required replacement or repair.24 Reportswere excluded if they failed to report tooth vitality and thenumber of remaining coronal walls or restored surfaces.Reports were also excluded if the studies did not differ-entiate among anterior teeth, third molars, or the primarydentition; or included periodontally compromised teeth;
THE JOURNAL OF PROSTHETIC DENTISTRY
reported indirect restorations other than tooth-supportedcomplete crowns such as inlays or implant crowns; hada pool of participants in which more than 25% werebruxers; or restorations were placed on removable partialdenture abutments.
After deleting duplicates, the 2 reviewers (K.I.A.,M.A.) independently screened the titles and abstractsidentified through the initial search and selected eligiblearticles for full review (Fig. 1). Intrareviewer calibrationwas carried out using the Cohen kappa test. The kappacoefficient was 0.90, indicating an “almost perfect”agreement25 between the 2 reviewers. Disagreementswere discussed and resolved by consensus. The full copyof all potentially relevant studies was retained for a fullassessment. Data extraction, quality assessment, and riskof bias assessment are detailed in Supplemental Materialsection Methodology.
The data retrieved were organized into subgroupsaccording to the type of restoration and number of
Afrashtehfar et al
Table 1. Summary of characteristics of included 14 definitive studies
Study (Year)Country/Setting
StudyDesign/
Follow-up(y)
No. ofPatients/No. of
Restorationsat Baseline
Mean Age/Age
Range atBaseline
(y)Teeth
Restored
No. ofRemaining
Walls
Type ofRestorationMaterial
% Dropouts/Restorations Funding
Randomized controlledtrials
Bernardo et al2 (2007) Portugal/Uni RCT/7 507/1748 9.9/8-12 Premolar;Molar
0-4 Amalgams;Resins
6.9/ - Public institution
Kramer et al3 (2011) Germany/Pri RCT/6 30/66 32.9 /24-59 Premolar;Molar
Opdam et al15 (2004) The Netherlands/Uni Retrosp/5 382/703 - /22-78 Premolar;Molar
1-4 Resins NA NR
NA, not applicable; NR, not reported; Pri; private practice; Prosp, prospective; Pub, public clinic; RCT, randomized control trial; Retrosp, retrospective; Uni, University. aInformation notrelevant to this review (glass ionomers and/or compomers) not included in table. Maximum follow-up for all groups reported.
March 2017 347
remaining tooth walls. For each subgroup, the outcomewas treated as a continuous variable (0%-100%) reportedweighted arithmetic mean (WAM) 5-year failure ratecalculated using the following formula:
xe=Pn
i=1 wixiPni=1 wi
;
where xi = the average of sample i, and wi = size ofsample i.
A metaregression model was used to assess the cor-relation between the number of remaining tooth wallsand the WAM 5-year failure rates of the restorations.This was done for RCTs and observational studies com-bined and separately. All analyses were performed usingstatistical software (SAS v9.3; SAS Institute)26 (a=.05).
RESULTS
The electronic and manual search yielded 3241 articlesafter removal of duplicates (Fig. 1). An additional 67articles were obtained from the manual search of thereferences of review articles identified within the initial
Afrashtehfar et al
search. Of these 3308 articles, 3227 were excluded afterscreening the titles and abstracts, and 54 were furtherexcluded based on eligibility criteria (SupplementalTable 6). From the remaining 27 articles, only 6 weregenuine publications that had only 1 published manu-script per study2,6,8,11,12,14; however, the remaining 21articles included 13 follow-up publications of 8 genuinestudies (Supplemental Table 7); 3 studies3,4,9 werereported in 2 publications each, 4 studies5,7,10,15 werereported in 3 publications each, and 1 study13
was reported in 6 publications. After the redundantpublications were removed, only 14 studies2-15 wereincluded (Table 1). They consisted of 5 RCTs2-6 and 9observational studies, of which 6 were prospective7-9,11,12,14 and 3 were retrospective.10,13,15
Study outcomes were presented as the number ofrestorations lost, retention rates, cumulative failure rates(%), or modified United States Public Health Service(USPHS) criteria scores. The WAM 5-year failure rate foreach specific condition indicated that the failure rate washigher in teeth with less remaining structure (fewer than2 remaining walls) (see Fig. 3D). These differences were
THE JOURNAL OF PROSTHETIC DENTISTRY
0 20 40 60 80 100
Sequence generation
Sequ
ence
gen
erat
ion
Concealment of allocation
Conc
ealm
ent o
f allo
catio
n
Handling of withdrawals
Han
dlin
g of
with
draw
als
Intention-to-treat analysis
Inte
ntio
n-to
-tre
at-a
naly
sis
Blinding: assessment
Blin
ding
: out
com
es a
sses
smen
t
Le
ve
l o
f E
vid
en
ce
A
BRisk of Bias (%)
Bernardo 2007
Kramer 2011
Manhart 2010
Plasmans 1993
Shi 2010
C
C
C
B
B
Adequate
Inadequate
Unclear/not specified
Not applicable/not feasible
+
+
+
+ + + +
+++
+ + + +
–
?
? ? ?
? ? ? ?
?
?
?
Figure 2. Risk of bias. A, Risk of bias summary: review authors’judgments about each risk of bias item for each included study. B, Riskof bias graph: review authors’ judgments about each risk of bias itempresented as percentages across all included studies.
348 Volume 117 Issue 3
more pronounced for composite resins than for amal-gams or crowns. Composite resins had a significantlyhigher failure rate than amalgams, regardless of theremaining tooth structure (P<.05) (SupplementalTable 8). In teeth with fewer than 2 remaining walls,direct restorations presented significantly higher failurerates than crowns (P<.05) (Supplemental Table 9).
The quality risk of bias assessment for RCTs is pre-sented in Figure 2, and the Strengthening the Reporting ofObservational Studies in Epidemiology (STROBE)-basedquality appraisal for observational studies is available inSupplemental Table 10 and Table 2. Among the 5 RCTsincluded, the sequence generation, concealment ofallocation, handling of withdrawals, intention-to-treat
THE JOURNAL OF PROSTHETIC DENTISTRY
analysis, and blinding were adequate in 3, 1, 4, 3, and 2studies, respectively (Fig. 2A). The risk of bias acrossstudies is presented as percentages in Figure 2B. Thehandling of withdrawals and drop-outs was adequatelydescribed in 4 studies.3-6 The estimated risk of bias wasconsidered moderate (intermediate level of evidence) in 2studies4,6 and high in three studies.2,3,5 Regarding studydesign assessment following the American Association ofCritical-Care Nurses (ACCN) level of evidence (where A isthe highest level and M the lowest),27 3 RCTs2,3,5 wereranked as C (low level), and 2 RCTs4,6 were classified as B(moderate level) (Fig. 2A).
Among the 9 observational studies included, 3studies10,11,13 were classified as high level of quality ofreporting according to the Olmos criteria,28 5 as moder-ate level,7-9,14,15 and 1 as low level (Table 2).12 Mostobservational studies presented deficiencies (partial orincomplete) according to the STROBE criteria in report-ing the following items: title and abstract, study design,variables, main results, additional analyses, generaliz-ability, and funding. In contrast, the remaining sectionsof the STROBE criteria were met in most of the studies(Supplemental Table 10). The study design level of evi-dence was ranked as C for all included observationalstudies according to ACCN’s criteria (Table 2).
From the 14 selected studies, a total of 308 744 directand indirect restorations were identified. Of these resto-rations, 358 were single crowns, 4804 were compositeresins, and 303 582 were amalgams. The sample size ofeach study ranged from 478 to 300 470 restorations.11
Participants included in each study ranged from 30 to82 537.3,13 The age range of participants in these studiesvaried between 6 and 80 years of age.11,13 The mean age ofparticipants across the studies was 29 years old, althoughthis did not take into account 3 studies in which the meanage was not extractable13,15 or the number of participantswas not reported.12 Drop-out ranged from 0%3 to31.5%.10 Participants were recruited from dental clinicsacross various universities,2,4-8,10,12,15 private offices,3,5,14
and public health centers.9,11,13 Of the 14 includedstudies, 2 studies reported support from private com-panies3,4 and 6 from public institutions,2,7,9-11,13 1 studyreported financial support from both a private companyand a public institution,5 and 5 studies did not report anysources of support.6,8,12,14,15 Twelve studies examinedrestorations in molars and premolars and 2 studies4,5 onlyin molars. Seven studies3,4,6,8,9,12,15 assessed only com-posite resin restorations and 3 studies5,7,13 only amalgams.Three studies2,11,14 compared amalgams with compositeresins, and 1 study10 compared amalgams with crowns. Allsingle crowns were retrieved from 1 study,10 63% of thecomposite resins were reported by 1 study,11 and 99% ofthe amalgams included were reported by 1 study.13
Most of the studies (10 of 14) were located in Europe;4 studies were located in the United States,10 Turkey,8
Figure 3. Graphic representation of 5-year accumulated failure rate of restorative treatments according to remaining coronal structure in vitalteeth. A, Data pooled from both observational studies and randomized controlled trials (RCTs). B, Data from Fig. 3A without influencing studies(Kopperud et al11 and Lucarotti et al13). C, Data from only observational studies. D, Data from only RCTs. WAM, weighted arithmetic mean.
March 2017 349
and China.6,12 All included studies were published inEnglish, except for one,12 which was reported in Chinese.All included studies were published between 19935,7,14
and 2012.11 A wide range of follow-up (3 to 10 years)was reported across all the included studies.
DISCUSSION
Discerning whether a direct or an indirect restoration isthe better treatment option requires an assessment ofpossible confounders. To our knowledge, this is the first
Afrashtehfar et al
systematic review of the clinical failure of restorations inposterior permanent vital teeth that considers the num-ber of remaining walls as a key risk factor, rendering itvery relevant for clinical decision-making.
Fourteen studies2-15 involving 308 744 restorationsand over 1902 patients were included in this review; 2 ofthe 5 RCTs4,6 (Fig. 2A) and 3 of the 9 observationalstudies10,11,13 were judged as having low-risk of bias(Table 2). The RCTs showed that in teeth with fewer than2 remaining walls, crowns were better than amalgams,and regardless of the remaining tooth structure,
THE JOURNAL OF PROSTHETIC DENTISTRY
Table 2.Overall quality appraisal of observational studies included
Study, Year, Location
No. of ApplicableQuality Appraisal
Criteria Fulfilled (%)
Classification ofReport Accordingto Olmos et al28
Level of EvidenceAccording to AACN’s NewEvidence-Leveling System27
Akerboom et al7 1993, The Netherlands 11 (50) B C
Kiremitci et al,8 2009, Turkey 12 (55) B C
Kohler et al,9 2000, Sweden 13 (59) B C
Kolker et al,10 2005, United States 21 (96) A C
Kopperud et al,11 2012, Norway 20 (91) A C
Lin et al,12 1997, China 10 (46) C C
Lucarotti et al,13 2005, England 19 (86) A C
Mjor et al,14 1993, Norway 12 (55) B C
Opdam et al,15 2004, The Netherlands 17 (77) B C
Olmos classification criteria: A, high level, study in agreement with more than 80% of the STROBE criteria; B, moderate level, 50%-80% of STROBE criteria were fulfilled; C, low level, lessthan 50% criteria could be achieved. ACCN level of evidence: C, qualitative studies, descriptive or correlation studies, integrative reviews, systematic reviews, or randomized trials withinconsistent results. AACN, American Association of Critical Care Nurses; STROBE, Strengthening the Reporting of Observational Studies in Epidemiology.
350 Volume 117 Issue 3
amalgams presented better outcomes than compositeresins. We discuss the treatment options according to theremaining tooth structure below.
Teeth with 4 remaining wallsThe data retrieved seemed to indicate that amalgam res-torations might be the better option in teeth with 4remaining walls, although composite resins also per-formed well in this situation. The only RCT2 that directlycompared amalgams to composite resins and anotherRCT6 that did not compare them directly indicated thatcomposite resins presented a significantly higher failurerate than amalgams (Fig. 3D). Surprisingly, the data of the3 observational studies (which did not directly comparecomposite resins with amalgams) presented the oppositeresults (P<.05) (Fig. 3C). This was probably because 2 ofthese observational studies only reported amalgam res-torations, and they were extremely large. This renderedthe data for amalgams 80 times the data available forcomposite resins (Table 2).11,13 Interestingly, the WAMvalues calculated without these 2 influencing studies11,13
confirmed the RCTs showing that amalgam failure ratewas lower than that of composite resins (Fig. 3B). No in-formation was available for crowns for teeth with 4remaining walls (Table 3), probably because of the “soundtissue preservation principle,” where harming theremaining tooth tissue would be unjustified because suf-ficient structure exists to support a direct restoration.29 Inaddition, this could be related to patients’ financial con-straints or preference. Indeed, an important benefit ofusing direct restorations instead of crowns is the lowercost and ease of access for vulnerable populations.30
Teeth with 3 remaining wallsThe evidence gathered suggests that amalgams are thebest choice in teeth with 3 remaining walls (Fig. 3B, D).The only RCT2 comparing composite resins with amal-gams in teeth with 3 remaining walls concluded that theamalgams failed 2 times less often than composite resins
THE JOURNAL OF PROSTHETIC DENTISTRY
(Fig. 3D). This is in agreement with a previous narrativereview that advised against using composite resins inposterior multisurface restorations.31 The observationalstudies presented contradicting results (Fig. 3C) but wereof lower quality than the RCT and presented 45 times lessdata on composite resins (Table 3). No information oncrowns in teeth with 3-remaining walls was available,probably because of the same sound tissue preservationprinciple mentioned above.
Teeth with 2 remaining wallsAgain, amalgams seemed to be the material of choice. AllRCTs agreed that amalgams present better outcomesthan composite resins in teeth with 2 remaining walls(Table 3; Fig. 3D), and this is also in agreement with aprevious narrative review.31 The observational studiesopposed the results of the RCTs (Fig. 3C), but there wereno direct comparisons between amalgams and compositeresins in the observational studies (Table 3). No infor-mation was available on crowns for teeth with 3remaining walls.
Teeth with 1 remaining wallThe studies included here suggested that crowns werethe best choice for vital teeth with 1 remaining wall,followed by amalgam restorations. The only RCT2
comparing amalgams with composite resins in this sce-nario showed that amalgams outperformed compositeresins (Table 3; Fig. 3D), and the only observational studycomparing crowns with amalgams reported 4 times morefailures in amalgams (Table 3; Fig. 3C).10 Similar con-clusions were made by pooling data from studies notmaking direct amalgam-crown comparisons (Fig. 3A, B).
Teeth with less than 1 remaining wallRCTs comparing composite resin restorations withamalgams on vital teeth with less than 1 remaining wallshowed that composite resins failed twice as often(Fig. 3D); moreover, an observational study10 comparing
Afrashtehfar et al
Table 3. Failure rates of tooth restorations in vital teeth according to remaining tooth structure
Amalgam Resin Crown
Ref F (y) N Failure % Ref F (y) N Failure % Ref F (y) N Failure %
Less than a wall
5a,b 4 255 10 2a 7 12 50 10a 5 358 12.3
10a 5 398 48 10a 10 263 22
10a 10 255 63.9
2a,b 7 11 18.2
One wall
5a,b 4 255 10 2a,b 7 12 50 10a 5 358 12.3
2a,b 7 11 18.2 4 4 13 7.7 10a 10 263 22
10a 5 398 48 15 5 60 18
10a 10 255 63.9
Two walls
46b 15 658 12.1 9b 5 9 33.3 - - - -
2b 7 78 11.5 2b 7 74 33.8 - - - -
13 5 60 295 40 3b 6 16 0 - - - -
13 10 60 295 57 4b 4 17 5.9 - - - -
7 10 777 9.4 15 5 95 27 - - - -
Three walls
46b 15 459 8.5 9b 5 49 26.5 - - - -
2b 7 338 9.5 2b 7 356 19.4 - - - -
13 5 163 767 36 8 6 44 4.5 - - - -
13 10 163 767 51 14 5 36 16.7 - - - -
14 5 33 9.1 11 4.6 2800 12.4 - - - -
11 4.6 135 17.8 3b 6 52 0 - - - -
7 10 648 4.9 4b 4 40 5 - - - -
15 5 266 14 - - - -
Four walls
2b 7 429 1.2 2b 7 450 6.4 - - - -
13 5 76 418 28 12 3 125 14.4 - - - -
13 10 76 418 42 4b 4 13 7.7 - - - -
15 5 282 7 - - - -
6b 3 80 7.5 - - - -
-, no studies were found reporting these conditions. F, follow-up in years; N, number of restorations; Ref, reference of study. aStudy repeated on 1 and less than 1 remaining wall withoutdiscriminating between these scenarios. bReferences of RCTs.
March 2017 351
amalgams with crowns reported that crowns were better(Tables 2, 3; Fig. 3A-C). Accordingly, in teeth withless than 1 remaining wall, crowns may be the besttreatment option. However, dental implants shouldalso be considered, as implants have a lower failure rate(6%-10% at 5 years) than crowns on teeth missing alltheir coronal structure.32
Another important finding in our study was that,regardless of the treatment used, restorations failed moreoften in teeth with less remaining tooth structure. Thesefindings are in agreement with the recent literature33,34
reporting that risk increases by 30% to 40% for everyextra missing wall,33 and also composite resins fail 3.3times more often in posterior teeth with fewer than 2remaining walls than those with 4 remaining walls.35
Also, another study found that multiple-surface amal-gams failed more often than single-surface ones.32
Regarding the overall completeness and applicabilityof the evidence in this review, the included RCTs
Afrashtehfar et al
compared different composite resin brands,3,4,6 amal-gams with composite resins,2 and different amalgams.5
RCTs in prosthodontics are uncommon36-38 and oftenclassified as “low quality,”39 which is why we includedobservational studies to obtain data for a wider range ofclinical scenarios. However, observational studies provideweaker evidence than RCTs, and for this reason, ourdiscussion prioritized the data obtained from RCTswhenever possible. Also, to improve the quality ofreporting outcomes of this review, the WAM of RCTs andobservational studies were reported both separately andcombined (Fig. 3).
The follow-up period of the studies included rangedfrom 3 to 7 years. This was an important strength in thisreview because shorter studies have limited clinicalrelevance as most acceptable materials remain failure-free during the first few years.19,32,40 The analysis offailure rate was also a strength of this review because it isa definitive outcome that reflects an unequivocal benefit
THE JOURNAL OF PROSTHETIC DENTISTRY
352 Volume 117 Issue 3
to the patient and may directly affect clinical practice andpublic health policies.41
A weakness of this study was the variability in thefailure rate outcomes among the observational studiesbecause of the differences in settings, age of participants,caries risk, and teeth assessed (premolars versus molars).Indeed, in this review, premolar teeth were not analyzedseparately from molars because the data found in most ofthe included these studies did not differentiate betweenthem, although premolars tend to have less salvageabletooth structure than molars.32 Also, differences in theliners/bases and adhesives used may have influenced theresults of the composite resin studies. Another potentialsource of bias is that the USPHS criteria may not havebeen consistently applied across studies.42 In addition,even though most of the studies detailed the training andexperience of the operators, they were conducted mainlyin university settings (8 of 14) and in Europe (10 of 14);consequently, it is difficult to generalize the findings toother settings and regions. In addition, the quality ofreporting in the observational studies was low(Supplemental Table 10, Table 2), and the overall level ofevidence from the included studies was moderate in 2RCTs4,6 and low (C) in the rest of studies.
Regarding the quality of the evidence, this reviewpresents some degree of uncertainty, since the studiesincluded presented some risk of bias. Sample size cal-culations were neither conducted nor reported, andconsiderable variation was found in the methodologyand quality of the studies (Table 2; Fig. 2A). Anotherweakness in the included studies was the lack of blindingof both operators and evaluators; this is often unavoid-able in restorative dentistry RCTs (unlike other disci-plines) (Fig. 2) because the material and clinical protocolare impossible to conceal; and patient input could alsoaffect allocation concealment.41
Regarding the review process, the search strategy wasdeveloped by 2 experienced librarians and 2 reviewerswho scrutinized all identified references independently.However, the possibility that some references have beenmissed cannot be excluded. Additionally, the manualsearch of cross-references, relevant journals, and reviews,and the data extraction was done by only 1 reviewer(K.I.A.) (Supplemental Table 11).
This review has both clinical and research implicationsbecause it can help clinicians make better-informed de-cisions upon planning restorations of posterior vitalteeth, and it provides insight into areas of future research.Future clinical studies should be performed following therecommended guidelines (STROBE and CONSORT) andacross a wider range of settings including students,professors, and clinicians from private and public prac-tices.43,44 Additionally, treatment outcomes should beassessed as a function of a larger number of riskfactors45,46 over a suitable follow-up period and should
THE JOURNAL OF PROSTHETIC DENTISTRY
report failure based on reproducible and valid tools suchas the USPHS. Also, given the proposed discontinuationof amalgam, the long-term performance of new com-posite resin materials should be investigated.30
CONCLUSIONS
Despite its limitations, our study shows that restorationsin posterior vital teeth should be planned according tothe amount of remaining tooth structure because of therelationship with failure rate. In terms of treatmentselection, direct restorations are a valid option in poste-rior vital teeth with 2 or more remaining coronal walls;however, crowns may be preferred in teeth with lessremaining structure. Regardless of the amount ofremaining tooth structure in posterior teeth, amalgamseems to perform better than composite resin. Addi-tionally, our results encourage improvements in thereporting and standardization of primary studies toprovide more meaningful comparisons among restorativeinterventions.
REFERENCES
1. Sweet M, Damiano P, Rivera E, Kuthy R, Heller K. A comparison of dentalservices received by Medicaid and privately insured adult populations. J AmDent Assoc 2005;136:93-100.
2. Bernardo M, Luis H, Martin MD, Leroux BG, Rue T, Leitao J, et al.Survival and reasons for failure of amalgam versus composite posteriorrestorations placed in a randomized clinical trial. J Am Dent Assoc 2007;138:775-83.
3. Kramer N, Garcia-Godoy F, Reinelt C, Feilzer AJ, Frankenberger R.Nanohybrid vs. fine hybrid composite in extended class II cavities after sixyears. Dent Mater 2011;27:455-64.
4. Manhart J, Chen HY, Hickel R. Clinical evaluation of the posterior compositeQuixfil in class I and II cavities: 4-year follow-up of a randomized controlledtrial. J Adhes Dent 2010;12:237-43.
5. Plasmans PJ, van ’t Hof MA. A 4-year clinical evaluation of extensiveamalgam restorationsedescription of the failures. J Oral Rehabil 1993;20:561-70.
6. Shi L, Wang X, Zhao Q, Zhang Y, Zhang L, Ren Y, et al. Evaluation ofpackable and conventional hybrid resin composites in class I restorations:three-year results of a randomized, double-blind and controlled clinical trial.Oper Dent 2010;35:11-9.
7. Akerboom HB, Advokaat JG, Van Amerongen WE, Borgmeijer PJ. Long-termevaluation and rerestoration of amalgam restorations. Community Dent OralEpidemiol 1993;21:45-8.
8. Kiremitci A, Alpaslan T, Gurgan S. Six-year clinical evaluation of packablecomposite restorations. Oper Dent 2009;34:11-7.
9. Kohler B, Rasmusson CG, Odman P. A five-year clinical evaluation of class IIcomposite resin restorations. J Dentistry 2000;28:111-6.
10. Kolker JL, Damiano PC, Armstrong SR, Bentler SE, Flach SD, Caplan DJ,et al. Natural history of treatment outcomes for teeth with large amalgam andcrown restorations. Oper Dent 2004;29:614-22.
11. Kopperud SE, Tveit AB, Gaarden T, Sandvik L, Espelid I. Longevity of pos-terior dental restorations and reasons for failure. Eur J Oral Sci 2012;120:539-48.
12. Lin H, Wang J, Yan W. [A three-year clinical evaluation of five light-curedcomposite resins in fillings of posterior teeth]. Zhonghua Kou Qiang Yi XueZa Zhi 1997;32:242-5.
13. Lucarotti PS, Holder RL, Burke FJ. Analysis of an administrative database ofhalf a million restorations over 11 years. J Dent 2005;33:791-803.
14. Mjor IA, Jokstad A. Five-year study of Class II restorations in permanentteeth using amalgam, glass polyalkenoate (ionomer) cement and resin-basedcomposite materials. J Dent 1993;21:338-43.
18. Trushkowsky RD. Restoration of endodontically treated teeth: criteria andtechnique considerations. Quintessence Int 2014;45:557-67.
19. Demarco FF, Correa MB, Cenci MS, Moraes RR, Opdam NJ. Longevity ofposterior composite restorations: not only a matter of materials. Dent Mater2012;28:87-101.
20. Kawata T, Kawaguchi T, Yoda N, Ogawa T, Kuriyagawa T, Sasaki K. Effects ofa removable partial denture and its rest location on the forces exerted on anabutment tooth in vivo. Int J Prosthodont 2008;21:50-2.
22. Grembowski D, Fiset L, Milgrom P, Forrester K, Spadafora A. Factorsinfluencing the appropriateness of restorative dental treatment: an epide-miologic perspective. J Public Health Dent 1997;57:19-30.
23. Moher D, Shamseer L, Clarke M, Ghersi D, Liberati A, Petticrew M, et al.Preferred reporting items for systematic review and meta-analysis protocols(PRISMA-P) 2015 statement. Syst Rev 2015;4:1.
24. Heintze SD, Rousson V. Clinical effectiveness of direct class II restorationsdameta-analysis. J Adhes Dent 2012;14:407-31.
25. Viera AJ, Garrett JM. Understanding interobserver agreement: the kappastatistic. Fam Med 2005;37:360-3.
26. SAS Institute Inc. Base SAS 9.3 procedures guide. Cary: SAS Institute Inc;2011. p. 72-233.
27. Armola RR, Bourgault AM, Halm MA, Board RM, Bucher L, Harrington L,et al. Upgrading the American Association of Critical-Care Nurses’ evidence-leveling hierarchy. Am J Crit Care 2009;18:405-9.
28. Olmos M, Antelo M, Vazquez H, Smecuol E, Maurino E, Bai JC. Systematicreview and meta-analysis of observational studies on the prevalence offractures in coeliac disease. Dig Liver Dis 2008;40:46-53.
29. Afrashtehfar KI, Assery MK. Five considerations in cosmetic and estheticdentistry. J N J Dent Assoc 2014;85:14-5.
30. Rasines Alcaraz MG, Veitz-Keenan A, Sahrmann P, Schmidlin PR, Davis D,Iheozor-Ejiofor Z. Direct composite resin fillings versus amalgam fillings forpermanent or adult posterior teeth. Cochrane Database Syst Rev 2014;3:CD005620.
31. Lyons K. Ministry of H. Direct placement restorative materials for use inposterior teeth: the current options. N Z Dent J 2003;99:10-5.
32. Frencken JE, Sithole WD. National oral health survey Zimbabwe 1995:quality of restorations. SADJ 1998;53:435-8.
33. Opdam NJ, van de Sande FH, Bronkhorst E, Cenci MS, Bottenberg P,Pallesen U, et al. Longevity of posterior composite restorations: a systematicreview and meta-analysis. J Dent Res 2014;93:943-9.
34. Moura FR, Romano AR, Lund RG, Piva E, Rodrigues Junior SA, Demarco FF.Three-year clinical performance of composite restorations placed by under-graduate dental students. Braz Dent J 2011;22:111-6.
35. da Rosa Rodolpho PA, Cenci MS, Donassollo TA, Loguercio AD,Demarco FF. A clinical evaluation of posterior composite restorations: 17-yearfindings. J Dent 2006;34:427-35.
36. Contrepois M, Soenen A, Bartala M, Laviole O. Marginal adaptationof ceramic crowns: a systematic review. J Prosthet Dent 2013;110:447-54.e10.
Afrashtehfar et al
37. Takeichi T, Katsoulis J, Blatz MB. Clinical outcome of single porcelain-fused-to-zirconium dioxide crowns: a systematic review. J Prosthet Dent 2013;110:455-61.
38. Lang LA, Teich ST. A critical appraisal of the systematic review process:systematic reviews of zirconia single crowns. J Prosthet Dent 2014;111:476-84.
39. Pandis N, Polychronopoulou A, Eliades T. An assessment of quality char-acteristics of randomised control trials published in dental journals. J Dent2010;38:713-21.
40. Manhart J, Chen H, Hamm G, Hickel R. Buonocore Memorial Lecture.Review of the clinical survival of direct and indirect restorations inposterior teeth of the permanent dentition. Oper Dent 2004;29:481-508.
41. Bidra AS. Evidence-based prosthodontics: fundamental considerations, lim-itations, and guidelines. Dent Clin North Am 2014;58:1-17.
42. Chadwick B, Treasure E, Dummer P, Dunstan F, Gilmour A, Jones R, et al.Challenges with studies investigating longevity of dental restorationseacritique of a systematic review. J Dent 2001;29:155-61.
43. von Elm E, Altman DG, Egger M, Pocock SJ, Gotzsche PC,Vandenbroucke JP, et al. The Strengthening the reporting of observationalstudies in epidemiology (STROBE) statement: guidelines for reportingobservational studies. PLoS Med 2007;4:e296.
44. Moher D, Schulz KF, Altman DG, Group C. The CONSORT statement:revised recommendations for improving the quality of reports of parallel-group randomised trials. Clin Oral Investig 2003;7:2-7.
45. Afrashtehfar KI, Eimar H, Yassine R, Abi-Nader S, Tamimi F. Evidence-based dentistry for planning restorative treatments: barriers and potentialsolutions. Eur J Dent Educ 5 May 2016. doi: 10.1111/eje.12208. [Epubahead of print].
46. Kreulen CM, Tobi H, Gruythuysen RJ, van Amerongen WE, Borgmeijer PJ.Replacement risk of amalgam treatment modalities: 15-year results. J Dent1998;26:627-32.
Corresponding author:Dr Faleh TamimiFaculty of Dentistry, McGill UniversityRm M64, 3640 University StMontreal, QCCANADAEmail: [email protected]
AcknowledgmentsThe authors thank librarians A. Lambreau, McGill University, and P. DuPont,University of Montréal, for their assistance in designing the electronic searchstrategies; and doctoral student O. Eilayyan, McGill University Faculty of Medi-cine, for conducting the statistical analysis.
1. Kopperud SE, Tveit AB, Gaarden T, Sandvik L, Espelid I. Longevity of pos-terior dental restorations and reasons for failure. Eur J Oral Sci 2012;120:539-48.
2. Mjor IA, Jokstad A. Five-year study of class II restorations in permanent teethusing amalgam, glass polyalkenoate (ionomer) cerment and resin-basedcomposite materials. J Dent 1993;21:338-43.
3. Higgins JPT, Green S; Cochrane Collaboration. Cochrane handbook forsystematic reviews of interventions. Hoboken: Wiley-Blackwell; 2012.
4. Emami E, Heydecke G, Rompre PH, de Grandmont P, Feine JS. Impact ofimplant support for mandibular dentures on satisfaction, oral and generalhealth-related quality of life: a meta-analysis of randomized-controlled trials.Clin Oral Implants Res 2009;20:533-44.
5. de Souza RF, Ahmadi M, Ribeiro AB, Emami E. Focusing on outcomes andmethods in removable prosthodontics trials: a systematic review. Clin OralImplants Res 2014;25:1137-41.
6. Ebell MH, Siwek J, Weiss BD, Woolf SH, Susman J, Ewigman B, et al.Strength of recommendation taxonomy (SORT): a patient-centered approachto grading evidence in the medical literature. Am Fam Physician 2004;69:548-56.
7. von Elm E, Altman DG, Egger M, Pocock SJ, Gotzsche PC,Vandenbroucke JP, et al. The Strengthening the Reporting of ObservationalStudies in Epidemiology (STROBE) statement: guidelines for reportingobservational studies. PLoS Med 2007;4:e296.
8. Olmos M, Antelo M, Vazquez H, Smecuol E, Maurino E, Bai JC. Systematicreview and meta-analysis of observational studies on the prevalence offractures in coeliac disease. Dig Liver Dis 2008;40:46-53.
9. Armola RR, Bourgault AM, Halm MA, Board RM, Bucher L, Harrington L,et al. Upgrading the American Association of Critical-Care Nurses’ evidence-leveling hierarchy. Am J Crit Care 2009;18:405-9.
10. Al-Samhan A, Al-Enezi H, Alomari Q. Clinical evaluation of posterior resincomposite restorations placed by dental students of Kuwait University. MedPrinc Pract 2010;19:299-304.
11. Burke FJT. Four year performance of dentine-bonded all-ceramic crowns. BrDent J 2007;202:269-73.
12. Busato AL, Loguercio AD, Reis A, Carrilho MR. Clinical evaluation of pos-terior composite restorations: 6-year results. Am J Den 2001;14:304-8.
13. Cloyd S, Gilpatrick RO, Moore D. Preventive resin restorations vs.amalgam restorations: a three-year clinical study. J Tenn Dent Assoc 1997;77:36-40.
14. da Rosa Rodolpho PA, Cenci MS, Donassollo TA, Loguercio AD,Demarco FF. A clinical evaluation of posterior composite restorations: 17-yearfindings. J Dent 2006;34:427-35.
15. Ferrari M, Cagidiaco MC, Goracci C, Vichi A, Mason PN, Radovic I, et al.Long-term retrospective study of the clinical performance of fiber posts. Am JDen 2007;20:287-91.
16. Ferrari M, Vichi A, Fadda GM, Cagidiaco MC, Tay FR, Breschi L, et al.A randomized controlled trial of endodontically treated and restored pre-molars. J Dent Res 2012;91:72S-8S.
17. Frankenberger R, Reinelt C, Kramer N. Nanohybrid vs. fine hybrid compositein extended class II cavities: 8-year results. Clin Oral Investig 2014;18:125-37.
18. Frencken JE, Sithole WD. National oral health survey Zimbabwe 1995:quality of restorations. SADJ 1998;53:435-8.
19. Gungor MA, Artunc C, Dundar M. Seven-year clinical follow-up study ofProbond ceramic crowns. Quintessence Int 2007;38:e456-63.
20. Kreulen CM, van Amerongen WE, Akerboom HB, Borgmeijer PJ,Gruythuysen RJ. Evaluation of occlusal marginal adaptation of Class II resin-composite restorations. ASDC J Dent Child 1993;60:310-4.
21. Kubo S, Kawasaki A, Hayashi Y. Factors associated with the longevity of resincomposite restorations. Dent Mater 2011;30:374-83.
22. Letzel H, van ’t Hof MA, Marshall GW, Marshall SJ. The influence of theamalgam alloy on the survival of amalgam restorations: a secondary analysisof multiple controlled clinical trials. J Dent Res 1997;76:1787-98.
23. Mair LH. Ten-year clinical assessment of three posterior resin compositesand two amalgams. Quintessence Int 1998;29:483-90.
24. Mancebo JC, Jimenez-Castellanos E, Canadas D. Effect of tooth type andferrule on the survival of pulpless teeth restored with fiber posts: a 3-yearclinical study. Am J Den 2010;23:351-6.
25. Mannocci F, Bertelli E, Sherriff M, Watson TF, Ford TR. Three-year clinicalcomparison of survival of endodontically treated teeth restored with eitherfull cast coverage or with direct composite restoration. J Prosthet Dent2002;88:297-301.
26. Mannocci F, Qualtrough AJ, Worthington HV, Watson TF, Pitt Ford TR.Randomized clinical comparison of endodontically treated teeth restoredwith amalgam or with fiber posts and resin composite: five-year results. OperDent 2005;30:9-15.
27. Moura FR, Romano AR, Lund RG, Piva E, Rodrigues Junior SA, Demarco FF.Three-year clinical performance of composite restorations placed by under-graduate dental students. Braz Dent J 2011;22:111-6.
28. Nikaido T, Takada T, Kitasako Y, Ogata M, Shimada Y, Yoshikawa T, et al.Retrospective study of the 10-year clinical performance of direct resin
353.e1 Volume 117 Issue 3
SUPPLEMENTAL MATERIAL
METHODOLOGYData extractionThe following data were extracted and recorded by 1reviewer (K.I.A.) into an electronic spreadsheet: names ofauthors, year of publication, country of the trial, studydesign, years of follow-up, characteristics of participants(age, gender, setting), drop-outs, type of restoration(prostheses, dental fillings), materials used in the resto-ration (amalgams, resins, and so on), tooth localization(molar, premolar, maxillary, mandibular), and outcomes.Lastly, based on the restoration material, the data (nrestorations, % failure) from the studies was categorizedinto groups according to remaining tooth structure priorto restoration. When important data were missing, areviewer (K.I.A.) attempted to contact the publications’authors to resolve ambiguity. However, only authorsfrom 2 studies added relevant information.1,2 For thetrials with multiple reports, only the outcome data fromthe most recent report were assigned as the main study.
Quality assessment and risk of biasTwo independent reviewers (K.I.A., M.A.) carried out themethodological quality assessment on the basis of thetype of the study.
For randomized controlled trials, the methodologicalquality of the trials was assessed using a domain-basedevaluation (Cochrane Collaboration tool), including re-ports of sample size estimation and 5 parameters ofquality: sequence generation, allocation concealment,completeness of follow-up, intention-to-treat analysis,and masking/blinding.3,4 Each parameter of trial meth-odological quality was graded as: “adequate,” “inade-quate,” “unclear,” or “not applicable.”5 Studies weredefined as having a low-risk of bias if the 5 criteria listedabove were clearly met in the study. If 1 or more of thesecriteria was not met, a study would be considered ashaving a moderate or high potential risk of bias,respectively. As an additional measure for thecompleteness of follow-up parameter, studies with morethan 20% attrition were considered to be “inadequate.”6
For the observational studies, the STrengthening theReporting of OBservational studies in Epidemiology(STROBE) statement was used to assess the study.7
STROBE provides a checklist with 22 items such as pre-specified hypothesis, sample size estimation, and reasonsfor dropout. Additionally, each study was categorizedaccording to the Olmos classification, where A = highlevel, that is, the study is in agreement with more than80% of the STROBE criteria; B = moderate level, that is,50%-80% of STROBE criteria were fulfilled; and C = lowlevel, that is, less than 50% criteria could be achieved.8
Finally, the level of evidence in the included studieswas assessed using the American Association of CriticalCare Nurses” (ACCN) new evidence-leveling system.9
THE JOURNAL OF PROSTHETIC DENTISTRY Afrashtehfar et al
composite restorations placed with the acid-etch technique. Quintessence Int2007;38:e240-6.
29. Pazinatto FB, Gionordoli Neto R, Wang L, Mondelli J, Mondelli RF,Navarro MF. 56-month clinical performance of Class I and II resin compositerestorations. J Appl Oral Sci 2012;20:323-8.
30. Peutzfeldt A, Sahafi A, Asmussen E. A survey of failed post-retained resto-rations. Clin Oral Investig 2008;12:37-44.
31. Sarrett DC, Brooks CN, Rose JT. Clinical performance evaluation of a packableposterior composite in bulk-cured restorations. J Am Dent Assoc 2006;137:71-80.
32. Signore A, Kaitsas V, Ravera G, Angiero F, Benedicenti S. Clinical evaluationof an oval-shaped prefabricated glass fiber post in endodontically treatedpremolars presenting an oval root canal cross-section: a retrospective cohortstudy. Int J Prosthodont 2011;24:255-63.
33. Smales RJ, Webster DA. Restoration deterioration related to later failure. OperDent 1993;18:130-7.
34. Sunnegardh-Gronberg K, van Dijken JW, Funegard U, Lindberg A,Nilsson M. Selection of dental materials and longevity of replaced restorationsin Public Dental Health clinics in northern Sweden. J Dent 2009;37:673-8.
35. Tobi H, Kreulen CM, Vondeling H, van Amerongen WE. Cost-effectiveness ofcomposite resins and amalgam in the replacement of amalgam class II res-torations. Community Dent Oral Epidemiol 1999;27:137-43.
36. Turkun LS, Aktener BO, Ates M. Clinical evaluation of different posteriorresin composite materials: a 7-year report. Quintessence Int 2003;34:418-26.
37. van Dijken JW, Pallesen U. A six-year prospective randomized study of anano-hybrid and a conventional hybrid resin composite in Class II restora-tions. Dent Mater 2013;29:191-8.
38. Adolphi G, Zehnder M, Bachmann LM, Gohring TN. Direct resin compositerestorations in vital versus root-filled posterior teeth: a controlled comparativelong-term follow-up. Oper Dent 2007;32:437-42.
39. Collins CJ, Bryant RW, Hodge KL. A clinical evaluation of posterior compositeresin restorations: 8-year findings. J Dent 1998;26:311-7.
40. Dammaschke T, Nykiel K, Sagheri D, Schafer E. Influence of coronal resto-rations on the fracture resistance of root canal-treated premolar and molarteeth: a retrospective study. Aust Endod J 2013;39:48-56.
41. Fokkinga WA, Kreulen CM, Bronkhorst EM, Creugers NH. Composite resincore-crown reconstructions: an up to 17-year follow-up of a controlled clinicaltrial. Int J Prosthodont 2008;21:109-15.
42. Geurtsen W, Schoeler U. A 4-year retrospective clinical study of Class I andClass II composite restorations. J Dent 1997;25:229-32.
43. Gomez-Polo M, Llido B, Rivero A, Del Rio J, Celemin A. A 10-year retro-spective study of the survival rate of teeth restored with metal prefabricatedposts versus cast metal posts and cores. J Dent 2010;38:916-20.
44. Hikasa T, Matsuka Y, Mine A, Minakuchi H, Hara ES, Van Meerbeek B, et al.A 15-year clinical comparative study of the cumulative survival rate of castmetal core and resin core restorations luted with adhesive resin cement. Int JProsthodont 2010;23:397-405.
45. Janus CE, Unger JW, Best AM. Survival analysis of complete veneer crownsvs. multisurface restorations: a dental school patient population. J Dent Educ2006;70:1098-104.
46. Juloski J, Fadda GM, Monticelli F, Fajo-Pascual M, Goracci C, Ferrari M. Four-year Survival of Endodontically Treated Premolars Restored with Fiber Posts.J Dent Res 2014;93:52S-8S.
47. Laegreid T, Gjerdet NR, Johansson AK. Extensive composite molar restora-tions: 3 years clinical evaluation. Acta Odontol Scand 2012;70:344-52.
48. Lundin SA, Koch G. Class I and II posterior composite resin restorations after5 and 10 years. Swed Dent J 1999;23:165-71.
49. Miyamoto T, Morgano SM, Kumagai T, Jones JA, Nunn ME. Treatment his-tory of teeth in relation to the longevity of the teeth and their restorations:outcomes of teeth treated and maintained for 15 years. J Prosthet Dent2007;97:150-6.
50. Nagasiri R, Chitmongkolsuk S. Long-term survival of endodontically treatedmolars without crown coverage: a retrospective cohort study. J Prosthet Dent2005;93:164-70.
51. Naumann M, Koelpin M, Beuer F, Meyer-Lueckel H. 10-year survival eval-uation for glass-fiber-supported postendodontic restoration: a prospectiveobservational clinical study. J Endod 2012;38:432-5.
52. Nordbo H, Leirskar J, von der Fehr FR. Saucer-shaped cavity preparations forposterior approximal resin composite restorations: observations up to 10years. Quintessence Int 1998;29:5-11.
53. Opdam NJ, Bronkhorst EM, Roeters JM, Loomans BA. Longevity and reasonsfor failure of sandwich and total-etch posterior composite resin restorations.J Adhes Dent 2007;9:469-75.
54. Palaniappan S, Elsen L, Lijnen I, Peumans M, Van Meerbeek B,Lambrechts P. Nanohybrid and microfilled hybrid versus conventional hybridcomposite restorations: 5-year clinical wear performance. Clin Oral Investig2012;16:181-90.
55. Rasmusson CG, Lundin SA. Class II restorations in six different posteriorcomposite resins: five-year results. Swed Dent J 1995;19:173-82.
56. Schmitter M, Hamadi K, Rammelsberg P. Survival of two post systemsefive-year results of a randomized clinical trial. Quintessence Int 2011;42:843-50.
57. Simecek JW, Diefenderfer KE, Cohen ME. An evaluation of replacement ratesfor posterior resin-based composite and amalgam restorations in U.S. Navyand marine corps recruits. J Am Dent Assoc 2009;140:200-9; quiz 49.
58. Smales RJ, Hawthorne WS. Long-term survival and cost-effectiveness of fivedental restorative materials used in various classes of cavity preparations. IntDent J 1996;46:126-30.
60. Sterzenbach G, Franke A, Naumann M. Rigid versus flexible dentine-likeendodontic postseclinical testing of a biomechanical concept: seven-year re-sults of a randomized controlled clinical pilot trial on endodontically treatedabutment teeth with severe hard tissue loss. J Endod 2012;38:1557-63.
61. Torres CR, Borges AB, Goncalves SE, Pucci CR, de Araujo MA, Barcellos DC.Clinical evaluation of two packable resin-based composite restorations: athree-year report. Gen Dent 2010;58:338-43.
62. Turkun LS, Turkun M, Ozata F. Clinical performance of a packable resincomposite for a period of 3 years. Quintessence Int 2005;36:365-72.
63. Van Nieuwenhuysen JP, D’Hoore W, Carvalho J, Qvist V. Long-term evalu-ation of extensive restorations in permanent teeth. J Dent 2003;31:395-405.
March 2017 353.e2
Afrashtehfar et al THE JOURNAL OF PROSTHETIC DENTISTRY
Supplemental Table 2. Search strategy used for CENTRAL
1. Longevity2. ([Exp TREATMENT OUTCOME])
or (success])3. (DENTAL RESTORATION FAILURE)
or (failure)4. DENTAL STRESS ANALYSIS5. ([prognos*) or (Exp PROGNOSIS])6. ([Exp SURVIVAL ANALYSIS) or
(Survival])7. FOLLOW UP STUDIES
8. DENTAL PROSTHESIS REPAIR9. (#1 or #2 or #3 or #4 or #5 or #6 or
#7 or #8)10. DENTAL AMALGAM11. ([RESINS) or (COMPOSITE RESINS) or
(COMPOMERS) or (Exp EPOXY RESINS])12. resin*13. composite*14. compomer*15. amalgam*
16. direct restor*17. conventional fill*18. dental filling*19. ([crown*) or (Exp CROWNS])20. full cast*21. (#10 or #11 or #12 or #13 or #15 or #16 or
#17 or #18 or #19 or #20)22. ([DENTAL RESTORATION) or (DENTITION) or
(TOOTH]) #23 #9 AND #21 AND #22
CENTRAL, Cochrane Central Register of Controlled Trials. Asterisk (*) used as truncation symbol.
Supplemental Table 3. Search strategy used for OVID MEDLINE + EPOCa
1. longevity.mp.2. exp Treatment Outcome/
or success.mp.3. Dental Restoration Failure/
or failure.mp.4. Dental Prosthesis Repair/5. Dental Stress Analysis/6. prognos$.mp. or exp Prognosis/7. exp Survival Analysis/ or Survival.mp.8. Follow-Up Studies/9. 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8
10. Dental Amalgam/11. Resins, Synthetic/ or Composite
Resins/ or Compomers/ or expEpoxy Resins/
12. resin$.mp.13. composite$.mp.12. resin$.mp.13. composite$.mp.14. compomer$.mp.15. amalgam$.mp.16. “direct restor$”.mp.17. “conventional fill$”.mp.18. “dental filling$”.mp.19. crown$.mp. or exp Crowns/20. full cast$.mp.21. 10 or 11 or 12 or 13 or 15 or 16 or
17 or 18 or 19 or 2022. dentistry, operative/ or dental restoration,
permanent/ or dentition/ or tooth/
23. 9 and 21 and 2224. randomized controlled trial.pt.25. controlled clinical trial.pt.26. randomized.ab.27. placebo.ab.28. clinical trials as topic.sh.29. randomly.ab.30. trial.ab.31. 24 or 25 or 26 or 27 or 28 or 29 or 3032. exp animals/ not humans.sh.33. 31 not 3234. 23 and 3335. limit 34 to yr=“1993 - 2015”
aMEDLINE, sensitivity- and precision-maximizing version (2008 revision Box 6.4d http://www.cochrane-handbook.org/).
Supplemental Table 4. Search strategy used for Embase, 1947 to February 2015
1. longevity.mp.2. exp treatment outcome/3. success.mp.4. failure*.mp.5. exp prognosis/ or prognos*.mp.6. survival.mp. or exp survival/7. exp follow up/8. durab*.mp.9. 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8
10. exp amalgam/11. resin/ or compomer/ or epoxy
resin/12. compomer/ or epoxy resin/13. resin*.mp.14. composite*.mp.15. compomer*.mp.
16. amalgam*.mp.17. “conventional fill*”.mp.18. “direct restor*”.mp.19. “dental filling*”.mp.20. crown*.mp.21. exp tooth crown/22. full cast*.mp.23. 10 or 11 or 12 or 13 or 14 or
15 or 16 or 17 or 18 or 19 or20 or 21 or 22
24. dental surgery/25. 9 and 23 and 2426. Randomized controlled trial/27. random$.tw.28. experiment$.tw.29. (time adj series).tw.
30. (pre test or pretest or post testor posttest).tw.
31. impact.tw.32. intervention$.tw.33. chang$.tw.34. evaluat$.tw.35. effect?.tw.36. compar$.tw.37. control$.tw.38. Nonhuman/39. or/26-3740. 39 not 3841. 25 and 4042. limit 41 to yr=“1993-2015”
Supplemental Table 5.Method information 1: journals selected forhand searching
Journal of ProsthodonticsInternational Journal of ProsthodonticsJournal of Prosthetic DentistryThe International Journal of Periodontics and Restorative DentistryJournal of Dental ResearchOperative DentistryJournal of the American Dental AssociationJournal of Dentistry
Supplemental Table 1. Search strategy used for Cochrane Oral Health Group’s Trials Register
(longevity or success or failure or repair or prognos* or survival or follow-up or follow up) AND (resin* or compomer* or composite* or amalgam* or “direct restor* or“conventional fill*” or “dental filling*” or crown* or full cast*) AND (dental or dentition or tooth)
353.e3 Volume 117 Issue 3
THE JOURNAL OF PROSTHETIC DENTISTRY Afrashtehfar et al
Supplemental Table 6. Full-text excluded articles and reasons for exclusion
Reason for Exclusion Articles Excluded
Not meeting inclusion criteriaa Al-Samhan et al10 (2010)Burke11 (2007)Busato et al12 (2001)Cloyd et al13 (1997)da Rosa Rodolpho et al14 (2006)Ferrari et al15 (2007)Ferrari et al16 (2012)Frankenberger et al17 (2014)Frencken and Sithole18 (1998)Gungor et al19 (2007)Kreulen et al20 (1993)Kubo et al21 (2011)Letzel et al22 (1997)Mair23 (1998)
Mancebo et al24 (2010)Mannocci et al25 (2002)Mannocci et al26 (2005)Moura et al27 (2011)Nikaido et al28 (2007)Pazinatto et al29 (2012)Peutzfeldt et al30 (2008)Sarrett et al31 (2006)Signore et al32 (2011)Smales and Webster33 (1993)Sunnegardh-Gronberg et al34 (2009)Tobi et al35 (1999)Turkun et al36 (2003)van Dijken and Pallesen37 (2013)
Inadequate datab Adolphi et al38 (2007)Collins et al39 (1998)Dammaschke et al40 (2013)Fokkinga et al41 (2008)Geurtsen and Schoeler42 (1997)Gomez-Polo et al43 (2010)Hikasa et al44 (2010)Janus et al45 (2006)Juloski et al46 (2014)Laegreid et al47 (2012)Lundin and Koch48 (1999)Miyamoto et al49 (2007)Nagasiri and Chitmongkolsuk50 (2005)
Naumann et al51 (2012)Nordbo et al52 (1998)Opdam et al53 (2007)Palaniappan et al54 (2012)Rasmusson and Lundin55 (1995)Schmitter et al56 (2011)Simecek et al57 (2009)Smales and Hawthorne58 (1996)Smales and Hawthorne59 (1997)Sterzenbach et al60 (2012)Torres et al61 (2010)Turkun et al62 (2005)Van Nieuwenhuysen et al63 (2003)
aNot meeting inclusion criteria: included articles which had unknown vitality status or only nonvital teeth no information on remaining walls, or were review articles. bInadequate data: “Data nonextractable” included articles which grouped surface information, no information combining remaining walls with restorative material and included bruxers, fixed dental prostheses (FDPs),and nontraditional types of restoration (saucer-shaped). “Invalid remaining structure description” included articles which were not describing coronal remaining walls or restored surfaces(for example >75% dentine wall circumferential, �1 cusp covered filling size, at least 40% of the crown had to be destroyed).
March 2017 353.e4
Afrashtehfar et al THE JOURNAL OF PROSTHETIC DENTISTRY
Supplemental Table 7. References to studies included in this review
Akerboom 1993* Akerboom HB, Advokaat JG, Van Amerongen WE, Borgmeijer PJ. Long-term evaluation and rerestoration of amalgam restorations. Community Dent Oral Epidemiol1993;21(1):45-8.Gruythuysen RJ, Kreulen CM, Tobi H, van Amerongen E, Akerboom HB. 15-year evaluation of Class II amalgam restorations. Community Dent Oral Epidemiol1996;24(3):207-10.Kreulen CM, Tobi H, Gruythuysen RJ, van Amerongen WE, Borgmeijer PJ. Replacement risk of amalgam treatment modalities: 15-year results. J Dent 1998;26(8):627-32.
Bernardo 2007Bernardo M, Luis H, Martin MD, et al. Survival and reasons for failure of amalgam versus composite posterior restorations placed in a randomized clinical trial. J Am DentAssoc 2007;138(6):775-83.
Kiremitci 2009Kiremitci A, Alpaslan T, Gurgan S. Six-year clinical evaluation of packable composite restorations. Oper Dent 2009;34(1):11-7.
Kramer 2011Kramer N, Reinelt C, Richter G, Petschelt A, Frankenberger R. Nanohybrid vs. fine hybrid composite in Class II cavities: clinical results and margin analysis after four years.Dent Mater 2009;25(6):750-9.* Kramer N, Garcia-Godoy F, Reinelt C, Feilzer AJ, Frankenberger R. Nanohybrid vs. fine hybrid composite in extended Class II cavities after six years. Dent Mater2011;27(5):455-64.
Kohler 2000Rasmusson CG, Kohler B, Odman P. A 3-year clinical evaluation of two composite resins in class-II cavities. Acta Odontol Scand 1998;56(2):70-5.* Kohler B, Rasmusson CG, Odman P. A five-year clinical evaluation of Class II composite resin restorations. J Dent 2000;28(2):111-6.
Kolker 2004* Kolker JL, Damiano PC, Armstrong SR, et al. Natural history of treatment outcomes for teeth with large amalgam and crown restorations. Oper Dent 2004;29(6):614 -22.Kolker JL, Damiano PC, Jones MP, et al. The timing of subsequent treatment for teeth restored with large amalgams and crowns: factors related to the need forsubsequent treatment. J Dent Res 2004;83(11):854-8.Kolker JL, Damiano PC, Caplan DJ, et al. Teeth with large amalgam restorations and crowns: factors affecting the receipt of subsequent treatment after 10 years. J AmDent Assoc 2005;136(6):738-48; quiz 805-6.
† Kopperud 2012Kopperud SE, Tveit AB, Gaarden T, Sandvik L, Espelid I. Longevity of posterior dental restorations and reasons for failure. Eur J Oral Sci 2012;120(6):539-48.
Lin 1997Lin H, Wang J, Yan W. [A three-year clinical evaluation of five light-cured composite resins in fillings of posterior teeth]. Zhonghua Kou Qiang Yi Xue Za Zhi1997;32(4):242-5.
Lucarotti 2005Burke FJ, Lucarotti PS. How long do direct restorations placed within the general dental services in England and Wales survive? Br Dent J 2009;206(1): E2; discussion 26-7.* Lucarotti PS, Holder RL, Burke FJ. Analysis of an administrative database of half a million restorations over 11 years. J Dent 2005;33(10):791-803.Burke FJ, Lucarotti PS, Holder R. Outcome of direct restorations placed within the general dental services in England and Wales (Part 4): influence of time and place. JDent 2005;33(10):837-47.Burke FJ, Lucarotti PS, Holder RL. Outcome of direct restorations placed within the general dental services in England and Wales (Part 2): variation by patients’characteristics. J Dent 2005;33(10):817-26.Lucarotti PS, Holder RL, Burke FJ. Outcome of direct restorations placed within the general dental services in England and Wales (Part 3): variation by dentist factors. JDent 2005;33(10):827-35.Lucarotti PS, Holder RL, Burke FJ. Outcome of direct restorations placed within the general dental services in England and Wales (Part 1): variation by type of restorationand re-intervention. J Dent 2005;33(10):805-15.
Manhart 2010Manhart J, Chen HY, Hickel R. Three-year results of a randomized controlled clinical trial of the posterior composite QuiXfil in class I and II cavities. Clin Oral Investig2009;13(3):301-7.* Manhart J, Chen HY, Hickel R. Clinical evaluation of the posterior composite Quixfil in class I and II cavities: 4-year follow-up of a randomized controlled trial. J AdhesDent 2010;12(3):237-43.
Mjor 1993Mjor IA, Jokstad A. Five-year study of Class II restorations in permanent teeth using amalgam, glass polyalkenoate (ionomer) cerment and resin-based compositematerials. J Dent 1993;21(6):338-43.
Opdam 2004* Opdam NJ, Loomans BA, Roeters FJ, Bronkhorst EM. Five-year clinical performance of posterior resin composite restorations placed by dental students. J Dent2004;32(5):379-83.Opdam NJ, Bronkhorst EM, Roeters JM, Loomans BA. A retrospective clinical study on longevity of posterior composite and amalgam restorations. Dent Mater2007;23(1):2-8.Opdam NJ, Bronkhorst EM, Loomans BA, Huysmans MC. 12-year survival of composite vs. amalgam restorations. J Dent Res 2010;89(10):1063-7.
Plasmans 1993* Plasmans PJ, van ’t Hof MA. A 4-year clinical evaluation of extensive amalgam restorations–description of the failures. J Oral Rehabil 1993;20(6):561-70Plasmans PJ, Creugers NH, Mulder J. Long-term survival of extensive amalgam restorations. J Dent Res 1998;77(3):453-60.Plasmans PJ, Creugers NH, Mulder J. [Long-term survival of extensive amalgam restorations]. Ned Tijdschr Tandheelkd 2000;107(6):233-7.
† Shi 2010Shi L, Wang X, Zhao Q, et al. Evaluation of packable and conventional hybrid resin composites in Class I restorations: three-year results of a randomized, double-blind andcontrolled clinical trial. Oper Dent 2010;35(1):11-9.*Major publication for the study (signifies key publication). †Publication inclusion from hand search origin.
353.e5 Volume 117 Issue 3
THE JOURNAL OF PROSTHETIC DENTISTRY Afrashtehfar et al
Supplemental Table 8.Meta regression of 5-year mean failure rates interventions in comparison to amalgam in randomized control trials
Remaining Coronal Structure Intervention Beta-Coefficient SE 95% CL Z P
Less than a wall
Amalgam Reference
Resin 44.23 0.28 43.7 44.8 158.4 <.0001
One wall
Amalgam Reference
Resin 25.6 3.77 18.2 33 6.79 <.0001
Two walls
Amalgam Reference
Resin 12.26 1.12 10.05 14.5 10.90 <.0001
Three walls
Amalgam Reference
Resin 5.54 0.25 5.1 6 22.43 <.0001
Four walls
Amalgam Reference
Resin 5.15 0.12 5.4 -18.8 43.14 <.0001
CL, confidence limits; SE, standard error.
Supplemental Table 9.Meta regression of 5-year mean failure rates interventions in comparison to crowns according to data derived fromrandomized trials combined with observational studies
Remaining Coronal Structure Intervention Beta-Coefficient SE 95% CL Z P
Less than a wall
Crown Reference
Resin 34.90 0.00 34.90 34.90 - -
Amalgam 26.55 0.67 25.24 27.86 39.71 <.0001
One wall
Crown Reference
Resin 8.54 1.20 6.18 10.90 7.09 <.0001
Amalgam 26.60 0.69 25.29 27.90 39.82 <.0001
CL, confidence limits; SE, standard error.
March 2017 353.e6
Afrashtehfar et al THE JOURNAL OF PROSTHETIC DENTISTRY
Supplemental Table 10. Table of quality appraisal of observational studies included in this systematic review
Section and Topic Item
Referenceb
Akerboom,1993.Netherlands
Kiremitci,2009.Turkey
Kohler,2000.
Sweden
Kolker,2005.USA
Kopperud,2012.Norway
Lin,1997.China
Lucarotti,2005.
England
Mjor,1993.Norway
Opdam,2004.
Netherlands
Title and abstract 1 P P P Y N Y Y P P
Introduction
Background/ rationale 2 Y Y Y Y Y Y Y Y Y
Objectives 3 Y Y Y Y Y Y Y Y Y
Methods
Study design 4 Y N N Y N N N N Y
Setting 5 P N Y Y Y N Y N Y
Participants 6 Y Y Y Y Y Y Y Y Y
Variables 7 N P P Y Y P Y P Y
Data sources/ measurement 8a P Y Y Y Y Y Y Y Y
Bias 9 Y N N Y Y N Y Y N
Study size 10 N Y Y Y Y N Y N Y
Quantitative variables 11 Y Y Y Y Y Y Y Y Y
Statistical methods 12 N Y P Y Y P Y Y Y
Results
Participants 13a Y Y Y Y Y P Y P Y
Descriptive data 14a Y Y Y Y Y Y Y Y Y
Outcome data 15a Y Y Y Y Y Y Y Y Y
Main results 16 N N N Y Y N P N N
Other analyses 17 Y N N Y Y N N Y N
Discussion
Key results 18 Y Y Y Y Y Y Y Y Y
Limitations 19 N N P Y Y Y Y Y Y
Interpretation 20 N Y Y Y Y N Y N Y
Generalizability 21 N N N Y Y N Y N Y
Other information
Funding 22 N N Y N Y N Y N N
Total “Y” 11 12 13 21 20 10 19 12 17aGave information separately for cases and controls in case control studies and, if applicable, for exposed and unexposed groups in cohort and cross-sectional studies. bReported classifications: N,information not provided; P, information partially provided; Y, information available.
353.e7 Volume 117 Issue 3
THE JOURNAL OF PROSTHETIC DENTISTRY Afrashtehfar et al
1. Downer MC, et al. How long do routine dental restorations last? A systematic review. Br Dent J 1999;187:432-9.2. Bolla M, et al. Root canal posts for the restoration of root filled teeth. Cochrane Database Syst Rev 2007;1:CD004623.3. Fedorowicz Z, et al. Single crowns versus conventional fillings for the restoration of root filled teeth. Cochrane Database Syst Rev 2012;5:CD009109.4. Heintze SD, Rousson V. Clinical effectiveness of direct class II restorations - a meta-analysis. J Adhes Dent 2012;14:407-31.5. Pjetursson BE, et al. A systematic review of the survival and complication rates of all-ceramic and metal-ceramic reconstructions after an observation period of at least
3 years. Part I: Single crowns. Clin Oral Implants Res 2007;18(suppl 3):73-85.6. Wittneben JG, et al. A systematic review of the clinical performance of CAD/CAM single-tooth restorations. Int J Prosthodont 2009;22:466-71.7. Heintze SD, Rousson V. Fracture rates of IPS Empress all-ceramic crowns–a systematic review. Int J Prosthodont 2010;23:129-33.8. Wang X, et al. A systematic review of all-ceramic crowns: clinical fracture rates in relation to restored tooth type. Int J Prosthodont 2012;25:441-50.
Nonsystematic reviews
1. Roulet JF. Benefits and disadvantages of tooth-coloured alternatives to amalgam. J Dent 1997;25:459-73.2. Hickel R, et al. Clinical results and new developments of direct posterior restorations. Am J Dent2000;13(Spec No):41D-54D.3. Hondrum SO. The longevity of resin-based composite restorations in posterior teeth. Gen Dent 2000;48:398-404.4. Hickel R, Manhart J. Longevity of restorations in posterior teeth and reasons for failure. J Adhes Dent 2001;3:45-64.5. Jedynakiewicz NM, Martin N. Posterior restorations–a clinical view. J Adhes Dent 2001;3:101-10.6. Manhart J, et al. Direct posterior restorations: clinical results and new developments. Dent Clin North Am 2002;46:303-39.7. Manhart J, et al. Buonocore Memorial Lecture. Review of the clinical survival of direct and indirect restorations in posterior teeth of the permanent dentition. Op Dent
2004;29:481-508.8. Anonymous. Evidence-based review of clinical studies on restorative dentistry. J Endodont 2009;35:1111-5.9. Kovarik RE. Restoration of posterior teeth in clinical practice: evidence base for choosing amalgam versus composite. Dent Clin North Am 2009;53:71-6, ix.
10. Qvist V. Resin restorations: leakage, bacteria, pulp. Endod Dent Traumatol 1993;9:127-52.11. Barbakow F, et al. [Amalgam as the measure in filling therapy. A determination of its place]. Schweizer Monatsschrift fur Zahnmedizin 1994;104:1341-50.12. Wilson NH. The limitations of resin-bonded restorations. Annals of the Academy of Medicine, Singapore 1995;24:52-57.13. Eley BM. The future of dental amalgam: a review of the literature. Part 7: Possible alternative materials to amalgam for the restoration of posterior teeth. Br Dent J
1997;183:11-14.14. Blatz MB. Long-term clinical success of all-ceramic posterior restorations. Quintessence International 2002;33:415-26.15. Goodacre CJ, et al. Clinical complications in fixed prosthodontics. J Prosthet Dent 2003;90:31-41.16. Verrett RG, Garcia LT. The single-unit crown: factors for clinical success. Tex Dent J 2003;120:1128-35.17. Sarrett DC. Clinical challenges and the relevance of materials testing for posterior composite restorations. Dent Mater 2005;21:9-20.18. Bader JD, Shugars DA. Summary review of the survival of single crowns. Gen Dent 2009;57:74-81.19. Kassem AS, et al. Survival rates of porcelain molar crowns-an update. Int J Prosthodont 2010;23:60-62.20. Ferracane JL. Resin composite–state of the art. Dent Mater 2011;27:29-38.21. Demarco FF, et al. Longevity of posterior composite restorations: not only a matter of materials. Dent Mater 2012;28:87-101.
March 2017 353.e8
Afrashtehfar et al THE JOURNAL OF PROSTHETIC DENTISTRY
