Effect of Length and Implant Surface

8/13/2019 Effect of Length and Implant Surface

1/19

Review A Systematic Review and Meta-Analysis on the Effectof Implant Length on the Survival of Rough-SurfaceDental ImplantsSotirios Kotsovilis,* Ioannis Fourmousis, Ioannis K. Karoussis, and Christina Bamia

Background: A meta-analysis on the survival of short im-plants compared to conventional implants has never been per-formed. Therefore, the aim of this study was to address thefocused question Is there a signicant difference in survivalbetween short ( 8 or < 10 mm) and conventional ( 10 mm)rough-surface dental implants placed in 1) totally or 2) partiallyedentulous patients? by conducting a systematic review andmeta-analysis of prospective studies published in the dental lit-erature in the English language up to and including August2007.

Methods: PubMed and the Cochrane Central Register of Controlled Trials (CENTRAL) databases were scanned elec-tronically, and seven journals were searched manually. In therst phase of selection, titles and abstracts, and in the secondphase, full texts, were evaluated autonomously and in duplicateby two reviewers. Extensive contact with authors was carriedout in search of missing, unclear, or unpublished data.

Results: The electronic and manual search provided, re-

spectively, 1,056 and 14,417 titles and abstracts. In the secondphase of selection, the complete text of 300 articles was exam-ined, and 37 articles reporting on 22 patient cohorts wereselected. Meta-analyses revealed no statistically signicantdifference in survival between short ( 8 or < 10 mm) and con-ventional ( 10 mm) rough-surface implants placed in totallyor partially edentulous patients.

Conclusions: Within the limitations of thissystematic review,the placement of short rough-surface implants is not a less ef-cacious treatment modality compared to the placement of con-ventional rough-surface implants for the replacement of missing teeth in either totally or partially edentulous patients.

J Periodontol 2009;80:1700-1718.KEY WORDSDental implants; meta-analysis; systematic review.

T he placement of dental implantsis an efcacious method for thereplacement of missing teeth intotally 1,2 and partially 3,4 edentulous pa-tients as documented by systematicreviews. 5-9 During the early years of im-plant therapy and along the lines of theBra nemark protocol, 10 the use of im-plants with the highest feasible lengthwas advocated based on the axiom thatlonger implants would exhibit highersurvival rates and more favorable prog-nosis. 11 However, in many clinicalcases, placement of long implants wasproblematic due to limitations, such asthe location of the canal of the inferioralveolar nerve, the pneumatization of the maxillary sinus, and alveolar ridgedeciencies. 12-17

To overcome such conditions, the cli-nician today often continues to increasethe height of the alveolar ridge using ad-vanced surgical techniques, 12-17 such asguided bone regeneration, block graft-ing, maxillary sinus oor elevation, anddistraction osteogenesis, or bypassesanatomic structures, for instance by al-veolar nerve transposition. 12 Neverthe-less, these surgical procedures are casesensitive, technically demanding, timeconsuming, and might increase thepost-surgical morbidity and the total costand duration of therapy. The placementof short implants has been introducedas an alternative treatment strategy to

* Private practice, Athens, Greece. Department of Periodontology, School of Dentistry, University of Athens, Athens, Greece. Department of Hygiene, Epidemiology and Medical Statistics, Medical School, University

of Athens.

doi: 10.1902/jop.2009.090107

Volume 80 Number 11

1700


2/19

deviate from advanced surgical techniques. 18-20

There is no consensus in the dental literature on thedenition of short implants, which in various reviewshave been considered to have a length 7 mm, 18 8 mm, 20 or < 10 mm. 19

For many years, the effect of the length of dentalimplants on their short- and long-term prognosishas been a controversial issue. Some clinicians haveinculcated thedogma that short implant length resultsin reduced bone-to-implant contact, and thus, shortimplants would be expected to exhibit lower survivaland/or success rates compared to longer implants.According to another hypothesis, short implantsmay demonstrate short-term survival and/or successrates comparable with those of conventional im-plants, but on a long-term basis, short implants wouldbe more likely to fail if peri-implantitis occurred due tothe lower quantity of bone support.

The comprehensive review18

by Hagi et al. was therst systematic approach to produce the radical reap-praisal that clearly, surface geometry (machinedversus rough)plays a major role in performance of en-dosseous dental implants of lengths 7 mm or less,conrming previous original research reporting thatthe rough [ . . .] implant surface [ . . .] may have com-pensated for the shorter implant length. 21 Similarly,subsequent systematic reviews 19,20 reported compa-rable survival rates for short and conventional rough-surface implants. However, a meta-analysis on theeffect of implantlength on thesurvivalof rough-surface

implants has not been performed.Therefore,the objectiveof this study wasto addressthe focused question Is there a signicant differencein survival between short ( 8 or < 10 mm) and conven-tional ( 10 mm) rough-surface dental implantsplaced in 1) totally or 2) partially edentulous pa-tients? by conducting a systematic review andmeta-analysis of prospective studies published inthe dental literature in the English language up toand including August 2007.

MATERIALS AND METHODSSearch Strategy for Identication of Studies Electronic search. The PubMed database of the UnitedStates National Library of Medicine and the CochraneCentral Register of Controlled Trials (CENTRAL) of theCochrane Collaboration were used as electronic data-bases, and a literature search was accomplished with apersonal computer on articles published in English upto and including August 2007. Articles available onlinein electronic form before their publication in materialform were considered eligible for inclusion in the pres-ent article.

The electronic search was carried out by applyingthe following terms and key words: (Dental OR

Oral) AND Implant* AND (Length OR ShortOR Shorter).

Manual search of journals. The following journalswere searched manually up to and including August2007 for the periods of time shown in parentheses:Clinical Oral Implants Research (1990 to 2007); Im- plant Dentistry (1994 to 2007); The International Journal of Oral and Maxillofacial Implants (1992 to2007); International Journal of Oral and Maxillofa- cial Surgery (1986 to 2007); The International Jour- nal of Periodontics and Restorative Dentistry (1991to 2007); Journal of Clinical Periodontology (1981 to2007); and Journal of Periodontology (1981 to 2007).

Other data sources. The reference lists of all iden-tied articles related to the topic were subjected toclose scrutiny. The authors attempted to search forthe maximum possible number of proceedings of pastworkshops, position papers, and theses. Whenever

deemed essential, missing, unclear, or unpublisheddata was sought by contact with authors.

Inclusion/Exclusion Criteria and Selection of Studies In the rst phase of study selection, the titles and ab-stracts of all identied publications were screened au-tonomously and in duplicateby tworeviewers (SKandIKK) to evaluate their eligibility for selection in thissystematic review on the basis of predetermined in-clusion and exclusion criteria.

Thefollowinginclusioncriteria were accepted byallreviewers:

1) Publications in thedental literature in theEnglishlanguage.

2) Only prospective studies.3) The presence of at least ve patients in each and

every group of the study andverough-surface dentalimplants with lengths < 10 mm, as well as at least verough-surface implants with lengths 10 mm (there-fore, studies lacking rough-surface implants of con-ventional length were not eligible for inclusion inthis systematic review).

4) The report of information on the characteristicsof study participants (principally inclusion and/or ex-clusion criteria) in the text of the study.

5) A clear report of (or report of data allowing thecalculation of) the total number of implants placed/surviving, either in totally edentulous or partiallyedentulous patients for implant lengths a) < 10 mmand b) 10 mm. In the event of a study comprisinga mixed population with totally and partially edentu-lous patients, all preceding data had to be providedseparately for totally and partially edentulous patientseither in the published manuscript or after contactwith the authors; otherwise, the study was not in-cluded.

J Periodontol November 2009 Kotsovilis, Fourmousis, Karoussis, Bamia

1701


3/19

An implant was dened as surviving if itwas not lost.The denition used in this article was provided by an-other systematic review, 22 according to which the lossof implants was dened as implant mobility of previ-ously clinically osseointegrated implants and removalof non-mobile implants due to progressive peri-im-plant marginal bone lossandinfection. If thedenitionof implant survival or implant loss in an examinedstudy was different from the denitions applied in thissystematic review, the study was not included.

Totally edentulous patients were dened as thosehaving no natural teeth in either jaw. Any patientclearly reported in an examined study as totally eden-tulous in one jaw and partially edentulous in the other jaw was considered to be partially edentulous , even if regarded as totally edentulous in the original study. If the denitions of a totally edentulous patient and a par-tially edentulous patient in an examined study were

clearly different from the denition applied in this sys-tematic review, the study was not included.6) A clear report of the surface characteristics

(smooth or rough) of implants used. If a study com-prised both smooth- and rough-surface implants, aclear report of (or report of data allowing the calcula-tion of) the survival of rough-surface implants wasmandatory; otherwise, the study was not included.

7) A follow-up period 12 months.

The following exclusion criteria were agreed by allreviewers:

1) Studies with an unclear or mixed design (for ex-ample: mixed prospective and retrospective data or if dental implants had been already placed before thecommencement of the study).

2) Smoking ( > 10 cigarettes/day).3) Medical or systemic diseases or conditions po-

tentially negatively affecting implant survival, suchas malignant tumors or past or current radiotherapyin the cervico-facial area, chemotherapy, leukocytedysfunction and deciencies, immunocompromisedpatients (e.g., positive for human immunodeciencyvirus), and diabetes not under metabolic control.

4) Dental implant placement in periodontally com-promised patients without previous implementationof periodontal therapy.

For all exclusion criteria (1 through 4), contact withthe authors of studies was carried out before nal ex-clusion. Exclusion of a study based on criteria 2through 4 was applied, unless the authors explicitlystated that these parameters did not correlate to im-plant survival rate or if all implants (100%) in the studyeventually survived.

In the second phase of selection, the complete ar-ticles of all studies already selected in the rst phase,as well as the full text of articles without abstracts or

articles with inadequate information in the title andabstract to allow a clear assessment, were acquired.Subsequently, these studies were evaluated indepen-dently and twice by two reviewers (SK and IKK) basedon the criteria for study selection/exclusion.

If more than one article corresponded to the sameclinical study, only the most recent data acceptableunder the inclusion/exclusion criteria applied in thissystematic review were used.

Any disagreement ensuing among the reviewerswould be resolved by discussion. If the divergencepersisted, it would be mentioned and analyzed in thissystematic review.

Data Extraction In accordance with previous systematic reviews, 23,24a standardized process of extractingdata from studiesselected using specially designed data-extractionforms was performed in duplicate and independentlyby two reviewers (SK and IKK) regarding the maincharacteristics (e.g., study design, methods, partici-pants, interventions, and outcome measures/varia-bles) and outcomes of studies, with particularemphasis on implant survival data. Any other infor-mation deemed scientically interesting was alsorecorded. Authors of studies were contacted for clar-ication or missing information.

Quality Assessment of Selected Studies The quality assessment of the selected studies wascarried out autonomously and in duplicate by two re-viewers (SK and IKK) using certain criteria proposedin the dental literature. 25-27 The unanimously ac-cepted criteria for qualityassessment were as follows:A) a clear denition of inclusion and/or exclusion cri-teria (grading: 0 = no; 1 = yes); and B) completenessof follow-up (specied reasons for withdrawals anddropouts in each study group) (grading: 0 = no/notmentioned/not clear; 1 = yes/withdrawals or dropoutsdid not occur).

Agreement between the two reviewers (SK andIKK) with regard to quality-assessment scores foreach quality criterion was determined by the propor-tion (%) of inter-reviewer agreement and, likewise, byk score, which additionally incorporated an adjust-ment for the degree of agreement to be expected en-tirely by chance. 28-31 In the event of any discrepancybetween the reviewers (SK and IKK), an agreementwas reached by discussion; otherwise, the differentassessments of the study quality would be mentionedand explained in this article.

Quantitative Data Synthesis (statistical analysis) The primary outcome measure/variable was the per-centage of implants surviving out of the total number

Short Versus Conventional Implants Volume 80 Number 11

1702


4/19

placed. It should be noted that the primary outcomemeasure was not implant survival rate but, rather, im-plantsurvival risk because total exposure time of eachand every implant (included in studies selected) wasnot available. No secondary outcome measures/var-iables were used. The associations of the survival of implants with their lengths (short versus conven-tional) were expressed as risk ratios (RRs). By deni-tion, RR > 1 indicated a higher percentage of survivingshort implants than conventional implants.

Publication bias was examined by using the BeggandMazumdars rankcorrelation test 32 and the Egger re-gression asymmetry test. 33 The Begg and Mazumdarsfunnel plot of the log RRs versus their standard errorwas calculated for studies reporting on short versusconventional rough-surface implants placed in totallyor partially edentulous patients.

The pooled RRs from combinations of studies, with

the associated 95% condence intervals, were ob-tained through meta-analyses performed separatelyfor totally and partially edentulous patients. Becausethe calculation of RR is undened if the values of oneor more cells in the cross table are equal to zero, 0.5was added to the values of all cells in such cases, fol-lowing the suggestions by Gart and Zweifel 34 andFleiss. 35 Heterogeneity among the selected studieswas assessed using the Q-statistic test. A random-effects model (DerSimonian-Laird method) of meta-analysis was used in the presence of heterogeneity(P < 0.10). All statistical analyses were carried out us-

ing a commercially available software program.

RESULTSStudy Selection and Classication (Tables 1 through 3) The electronic search in both databases (PubMed andCENTRAL) provided a total of 1,056 titles and ab-stracts that were deemedpotentially relevant to thein-uence of dental implant length on implant survival.During the manual search of dental journals, 14,417titles and abstracts were totally examined.

In the second phase of study selection, the com-plete text of 300 articles was retrieved and subjectedto close scrutiny. Throughout this procedure, 263 ar-ticles, corresponding to 220 studies, were excluded(Table 1).

Eventually, 37 articles 36-72 reporting on 22 patientcohorts were selected (Tables 2 and3). These articleswere further subdivided into two categories accordingto the type of edentulism (total or partial) of their par-ticipants: in 19 articles 36-54 reporting on eight patientcohorts, 36,39,41-43,45,47,49 implant survival data wereprovided for totally edentulous patients (Table 2); in23 articles 41,45-48,55-72 reporting on 17 patient co-horts, 41,45,47,55-58,63-72 implant survival data wereprovided for partially edentulous patients (Table 3).

Three studies 41,45,47 provided separate survivaldata both for totally and partially edentulous patients(Tables 2 and 3).

Results of Contact With Authors In total, additional information was sought throughelectronic mail for 125 articles, and answers werekindly provided by the authors of 72 articles (57.6%).

Results of Quality Assessment of Selected Studies With respect to quality criterion A, the rst reviewer(SK) was of the opinion that all 22 selected studieshad clearly dened inclusion/exclusion criteria. Ac-cording to the second reviewer (IKK), one study 55did not have clearly dened inclusion/exclusion crite-ria (the term high-risk conditions was not denedclearly), whereas another study 69 had clearly denedtoo few inclusion/exclusion criteria, which addition-ally were too vague and thus failed to provide a suf-

ciently explicit description of the characteristics of thestudy population included; the remaining 20 studieshad clearly dened inclusion/exclusion criteria.

With respect to quality criterion B, the reasons forpatient withdrawals/dropouts were clearly reportedin the published text of the majority of selected stud-ies, with the exception of three studies. 55,65,68

The overall proportion of inter-reviewer agreementwas 90.91% and 95.45% for quality criteria A andB, respectively, indicating an excellent 30 level of agreement in both cases. Concerning quality crite-rion A, the calculation of the k score was deemed

Table 1.

Number of Studies Excluded After SecondPhase of Selection

InclusionCriterionNot

Fullled

Studies

(n)

ExclusionCriterion

Fullled

Studies

(n)

1 0 1 14

2 41 2 4

3 75 3 11

4 0 4 3

5 69

6 2

7 1

Total 188 32 Stata/SE 8.0 for Windows, 2003, Stata, College Station, TX.


1703


5/19

Table 2.

Main Characteristics and Outcomes of Selected Prospective Studies Including TotallyEdentulous Patients

Reference(s)Implant

Type

Follow-Up(months;

mean[range])

Surviving/

Placed (%)Implants

WithL 8 mm

Surviving/

Placed (%)Implants

WithL < 10 mm

Surviving/

Placed (%)Implants

WithL 10 mm Other Information*

Geertman et al., 1996 36

(Boerrigter et al.. 1995;37

Kwakman et al., 199838 )

12[12 to 12]

19/19

(100%)19/19

(100%)62/63

(98.41%)1. No statistical comparison between

short and conventional implants.

2. All implants were placed in themandible; all short implants survived.

3. Implant-retained overdentureson two implants using a singlebar clip attachment.

4. No single-tooth implants.

Walmsley and Frame, 1997 39

(Walmsley et al., 1993 40 ) 60

[60 to 60]10/13

(76.92%)15/23

(65.22%)49/51

(96.08%)1. No statistical comparison

between short and conventionalimplants.

2. All implants were placed in theanterior mandible; survival of short< conventional implants.

3. Implant-retained overdentures on2 to 4 implants using magnets asretentive elements.


Brocard et al., 200041

i 48[12 to 84] 35/36

(97.22%) 35/36

(97.22%) 153/172

(88.95%) 1. No statistical comparison betweenshort and conventional implants.

2. Correlation implant survival-location: only 1 short implant waslost in a totally edentulous patientin the posterior maxilla; thus,data were not sufcient for subgroup analysis.

3. a) Implant-retained overdentureson 2 implants using clips asretentive elements; b) implant-supported xed full-arch (complete)restorations; c) implant-supported

xed partial restorations (dentures/bridges) in totally edentulouspatients.

4. No single-tooth implantsin totally edentulous patients.


1704


6/19

Table 2. (continued)


Reference(s)Implant

Type

Follow-Up(months;

mean[range])

Surviving/

Placed (%)Implants

WithL 8 mm

Surviving/

Placed (%)Implants

WithL < 10 mm

Surviving/

Placed (%)Implants


Meijer et al., 200442 107.8[0 to 120]

6/6

(100%)6/6

(100%)48/52



2. All implants were placed in theanterior mandible; all short implantssurvived.

3. Implant-retained overdentureson 2 implants using a round-shapedbar and a clip retention system.


Stellingsma et al., 200443

(Stellingsma et al., 200344 ) 24

[24 to 24] 56/56

(100%)56/56

(100%)24/24

(100%)1. Statistical comparison between

short and conventional implants notrequired/obviously NS.

2. All implants were placed in theanterior mandible; all implantssurvived.

3. Implant-retained overdentures on4 short implants using a triple bar with a clip retention system (study group III).


Fischer and Stenberg, 2006 45

(Fischer and Stenberg,2004 46 )

i 36[36 to 36]

8/8

(100%)8/8

(100%)34/34

(100%)1. Statistical comparison between

short and conventional implants notrequired/obviously NS.

2. All 42 implants were placedin the maxilla; all implantssurvived.

3. Implant-supported xed full-arch(complete) restorations on 5 or 6implants.


Romeo et al., 2006 47(Romeo et al., 2004 48 )

i 76.8[36 to 168]

25/26 (96.15%)

25/26 (96.15%)

43/44 (97.73%)

1. No statistical comparison betweenshort and conventional implants.

2. All lost implants had been placedin type III or IV bone, but their number was limited; NS.

3. Implant-supported xed completerestorations in totally edentulouspatients.

4. No single-tooth implantsin totally edentulous patients.


1705


7/19

meaningless ( k = 0) because of the complete absenceof cases with a score of 0 (zero) as applied by one re-viewer (SK), suggesting that, from a purely mathe-matic point of view, the chance-expected proportionof inter-reviewer agreement coincidedwith the overallproportion of inter-reviewer agreement. Accordingly,the actual inter-reviewer agreement might theoreti-

cally be explained purely on the basis of chance. 30,31Regarding quality criterion B, the k score was 0.775 0.309, representing a substantial 29 level of agree-ment beyond chance.

Results of Publication-Bias Evaluation (Fig. 1) Forboth denitions of short implants (length 8 or < 10mm), no evidence of publication bias ( P > 0.05 forboththe Begg and Mazumdars rank correlation test andthe Egger regression asymmetry test) was demon-strated for studies on totally or partially edentulouspatients. A typical example of the Begg and Mazum-dars funnel plot for one of these cases (for selectedstudies reporting on rough-surface implants with

lengths < 10 mm placed in partially edentulous pa-tients) is illustrated in Figure 1.

Meta-Analyses (Tables 2 through 4; Figs. 2 and 3) Survival of short versus conventional implants intotally edentulous patients (Tables 2 and 4; Fig. 2).When short implants were dened 8 or < 10 mmlong, six 36,39,41,42,47,49 of eight studies previouslyselected (Table 2) were included in the meta-analysis(Table 2, last row, and Table 4; Fig. 2). The remainingtwo studies 43,45 were not included because all shortand conventional implants survived and, thus, theRR could not be estimated (Fig. 2). For both deni-tions of short implants, no statistically signicant dif-ference ( P = 0.978) in survival was demonstratedbetween short and conventional rough-surface im-plants placed in totally edentulous patients (Table4; Fig. 2).

Survival of short versus conventional implants inpartially edentulous patients (Tables 3 and 4; Fig.3). When short implants were dened as 8 mm long,



Reference(s)Implant

Type

Follow-Up(months;

mean[range])

Surviving/

Placed (%)Implants

WithL 8 mm

Surviving/

Placed (%)Implants

WithL < 10 mm

Surviving/

Placed (%)Implants


Stoker et al., 200749

(Wismeijer, 1996; 50

Wismeijer et al., 1997,51,52

1999;53

Timmerman et al., 2004 54 )

i 100[18 to 118]

60/62

(96.77%)60/62

(96.77%)217/221



2. All implants were placed in themandible; tendency for survival of short implants < conventional.

3. Implant-retained overdentureson 2 (with a bar or ball attachments)or 4 (with a bar) implants.


Total in systematic review [0 to 168] 8 studies

219/226(96.90%)

8 studies

224/236(94.92%)

8 studies

630/661(95.31%)

Total in meta-analyses 6 studies #

155/162(95.68%)

6 studies#

160/172(93.02%)

6 studies#

572/603(94.86%)

L = length; NS = no signicant difference in survival between short and conventional implants.Articles in parentheses are sequenced according to publication year and, in the same year, alphabetically.* Other information includes: 1) statistical analysis (short versus conventional implants) in the original study; 2) survival of short versus conventional

implants according to implant location; 3) type of restoration; and 4) surviving/placed (%) splinted and non-splinted single-tooth short (L < 10 mm) andconventional (L 10 mm) implants.

Information retrieved after contact with the authors of the study. IMZ, Friatec, Friedrichsfeld, Mannheim, Germany. Astra Meditec, Astra Tech, Molndal, Sweden.i Straumann, Institute Straumann, Waldenburg, Switzerland. References 36, 39, 41-43, 45, 47, and 49.# References 36, 39, 41, 42, 47, and 49.


1706


8/19

Table 3.

Main Characteristics and Outcomes of Selected Prospective Studies Including PartiallyEdentulous Patients

Reference(s)Implant

Type

Follow-Up(months;

mean[range])

Surviving/

Placed (%)Implants

WithL 8 mm

Surviving/

Placed (%)Implants

WithL < 10 mm

Surviving/

Placed (%)Implants

WithL 10 mm

Other Information*

Buchs et al., 199655 NR [0 to 36]

83/83(100%)

83/83(100%)

339/340(99.71%)


2. All implants were placed in theposterior mandible; all shortimplants survived.

3. Implant-supported xed partialrestorations (dentures).


Deporter et al.,1998 56

NR [6 to 24]

None placed 13/13(100%)

7/7(100%)

1. Statistical comparison between shortand conventional implants notrequired/obviously NS.

2. All implants were placed in themaxilla; all implants survived.

3. Implant-supported single-toothrestorations (crowns).

4. All implants were non-splintedsingle-tooth.

Brocard et al., 200041 i 48

[0 to 84]

202/211

(95.73%)

202/211

(95.73%)

588/603

(97.51%)

1. No statistical comparison between

short and conventional implants.2. Correlation implant survival-location:

out of nine short implants lost inpartially edentulous patients: two inanterior maxilla, three in posterior maxilla, one in anterior mandible, three in posterior mandible.

3. a) Implant-supported single-toothrestorations (crowns); b) implant-supported xed partial restorations(dentures/bridges) in partially edentulous patients.

4. 112 single-tooth implants, all non-splinted (42/42 = 100% short and70/70 = 100% conventional survivedin partially edentulous patients).

van Steenbergheet al., 200057

24[24 to 24]

10/10(100%)

16/16(100%)

34/34(100%)


2. All implants survived, both in maxillaand mandible.

3. Implant-supported xed partialrestorations (dentures).



1707


9/19



Reference(s)Implant

Type

Follow-Up(months;

mean[range])

Surviving/

Placed (%)Implants

WithL 8 mm

Surviving/

Placed (%)Implants

WithL < 10 mm

Surviving/

Placed (%)Implants

WithL 10 mm

Other Information*

Deporter et al.,2001 58

(Deporter et al., 1999, 59

2000,60 2002;61

Rokni et al., 200562 )

34.6[5.1 to 68.6]

46/46(100%)

132/135(97.78%)

15/16(93.75%)

1. Univariate analyses/no detectablecorrelation between crestal boneloss and implant length (7, 9, or 12 mm).

2. All implants were placed in themaxilla; survival percentage of shortimplants was higher thanconventional implants.

3. a) Implant-supported single-toothrestorations (crowns); b) implant-supported xed partial restorations(dentures).

4. 66 non-splinted single-tooth implants(61/61 short and 5/5 conventionalsurvived).

Mericske-Sternet al., 200163

i 51.6[> 12 to 108]

46/49(93.88%)

46/49(93.88%)

60/60(100%)


2. Correlation implant survival-location:NR; number of lost short implants too low to allow a correlation.

3. Implant-supported single-toothrestorations (crowns).

4. All implants were non-splintedsingle-tooth.

Roccuzzoet al., 200164

i 12[12 to 12]

16/16(100%)

16/16(100%)

120/120(100%)


2. All implants survived, both in maxillaand mandible.

3. a) Non-splinted implant-supportedsingle-tooth restorations (crowns);

b) two splinted (attached) implant-supported single-tooth restorations(crowns); c) implant-supported xedpartial restorations (dentures)(3- or 4-unit).

4. 46 single-tooth implants, all non-splinted (22/22 short and 24/24conventional survived).


1708


10/19



Reference(s)Implant

Type

Follow-Up(months;

mean[range])

Surviving/

Placed (%)Implants

WithL 8 mm

Surviving/

Placed (%)Implants

WithL < 10 mm

Surviving/

Placed (%)Implants

WithL 10 mm

Other Information*

Cochran et al.,2002 65

i NR [0 to 24]Ongoingstudy; no

more recent(> 24 months)

follow-updata have

beenpublished

68/70(97.14%)

68/70(97.14%)

312/313(99.68%)


2. All implant losses occurred in themandible; NS.

3. a) Implant-supported xed partialrestorations (dentures) on 2implants; b) implant-supportedremovable denture restorations on 4 implants.


Roccuzzo andWilson, 2002 66

i 12[12 to 12]

9/9(100%)

9/9(100%)

26/27(96.30%)


2. All implants were placed in theposterior maxilla; all short implantssurvived.

3. a) Implant-supported single-toothrestorations (crowns); b) implant-supported xed partial restorations/dentures (short-span); c) implant/ tooth-supported xed par tialrestorations/dentures (long-span).

4. 11 single-tooth implants, all non-splinted and conventional, allsurvived.

Romeo et al., 2002 67 i 46[0 to 84]

11/11(100%)

11/11(100%)

115/119(96.64%)


2. All short implants survived; all lossesof conventional implants occurred in the posterior mandible.

3. Single-tooth restorations (crowns).4. All implants (short and conventional)

were single-tooth.

Romeo et al., 2003 68 i 47[12 to 84]

9/9

(100%)9/9

(100%)70/71


short and conventional implants.2. All short implants survived.3. Implant-supported xed partial

restorations (dentures) with a mesialor distal cantilever.

4. Nine single-tooth implants (1/1 shortand 8/8 conventional survived).


1709


11/19



Reference(s)Implant

Type

Follow-Up(months;

mean[range])

Surviving/

Placed (%)Implants

WithL 8 mm

Surviving/

Placed (%)Implants

WithL < 10 mm

Surviving/

Placed (%)Implants

WithL 10 mm

Other Information*

Frei et al., 200469 i 16[16 to 16]

11/11

(100%)11/11

(100%)66/66

(100%)1. Statistical comparison between short

and conventional implants notrequired/obviously NS.

2. All implants were placed in theposterior mandible; all implantssurvived.

3. NR.

4. NR.

Bornstein et al., 200570 i 58.59[0 to 60]

12/12

(100%)12/12

(100%)88/89



2. All implants were placed in posterior (maxillary or mandibular) regions;all short implants survived; oneconventional implant was lost in the mandible.

3. a) Implant-supported single-toothrestorations (crowns); b) implant-supported xed partial restorations(dentures).

4. 82 single-tooth implants. (43 splinted,39 non-splinted) (NR non-splintedshort, 37/39 = 94.87% non-splintedconventional, 12/13 = 92.31%splinted short, and NR splintedconventional survived).

Chiapasco et al., 2006 71 i 20.4[12 to 36]

8/8

(100%)8/8

(100%)85/87



2. All short implants survived.

3. a) Implant-supported single-toothrestorations (crowns); b) implant-supported xed partial restorations

(dentures).4. NR.


1710


12/19



Reference(s)Implant

Type

Follow-Up(months;

mean[range])

Surviving/

Placed (%)Implants

WithL 8 mm

Surviving/

Placed (%)Implants

WithL < 10 mm

Surviving/

Placed (%)Implants

WithL 10 mm

Other Information*

Fischer and Stenberg, 2006 45

(Fischer and Stenberg, 2004 46 )i 36

[36 to 36]18/19

(94.74%)18/19

(94.74%)79/81



2. 17 patients had partially edentulousmandibles at the 3-year follow-up;

unclear relation of survival to implantlocation.

3. In the maxilla: Implant-supportedxed full-arch (complete)restorations (dentures) on ve or siximplants. In the mandible: Onepatient with partially edentulousmandible who lost implants beforeloading had a mandibular full-archrestoration; no implant restoration in the remaining patients with partially edentulous mandibles.


Romeo et al., 2006 47

(Romeo et al., 2004 48 )i 76.8

[36 to 168]82/85

(96.47%)82/85

(96.47%)107/110

(97.27%)1. Multiple linear analysis/NS differences

in marginal bone loss and probingdepth values were observed

between short and standardimplants (P > 0.05).

2. All implants lost had been placed in type III or IV bone; NS.

3. a) Implant-supported single-toothrestorations (crowns); b) implant-supported xed partial restorations/dentures (without cantilevers); c)implant-supported xed partialrestorations/dentures with a mesialor a distal cantilever; d) implant/ tooth-supported xed par tialrestorations/dentures in partially edentulous patients.

4. 58 single-tooth implants: 29/29 =100% short and 28/29 = 96.55%conventional survived in partially edentulous patients.


1711


13/19



Reference(s)Implant

Type

Follow-Up(months;

mean[range])

Surviving/

Placed (%)Implants

WithL 8 mm

Surviving/

Placed (%)Implants

WithL < 10 mm

Surviving/

Placed (%)Implants

WithL 10 mm

Other Information*

Strietzel and Reichart, 200772 # 26.7[11 to 51]

None placed 35/35

(100%)132/134

(98.51%)1. Original study statistics not

meaningful in the context of thisreview/in this study, denition of short implants included11-mm implants.

2. All short implants survived;conventional implant losses were notrelated to implant location (anterior/

posterior or maxilla/mandible).3. a) Implant-supported single-tooth

restorations (crowns); b) implant-supported xed partial restorations(dentures); c) implant-retainedremovable partial dentures; d)implant-retained overdentures on2 implants.

4. 41 single-tooth implants, all non-splinted (4/4 = 100% short and36/37 = 97.30% conventionalsurvived).

Total in systematic review [0 to 168] 17 studies**631/649(97.23%)

17 studies**771/792(97.35%)

17 studies**2,243/2,277

(98.51%)

Total in meta-analyses 12 studies

594/612(97.06%)

13 studies

715/736(97.15%)

12 studies

1,884/1,916(98.33%)

13 studies

2,016/2,050(98.34%)

L = length; NS = no signicant difference in survival between short and conventional implants; NR = not reported.Articles in parentheses are sequenced according to publication year.* Other information includes: 1) statistical analysis (short versus conventional implants) in the original study; 2) survival of short versus conventional

implants according to implant location; 3) type of restoration; and 4) surviving/placed (%) splinted and non-splinted single-tooth short (L < 10 mm) andconventional (L 10 mm) implants.

Steri-Oss, Nobel Biocare, Yorba Linda, CA. Information retrieved (or not retrieved) after contact with the authors of the study. Endopore Implant System, Innova, Toronto, ON.i Straumann, Institute Straumann, Waldenburg, Switzerland. Astra Tech Implant Systems, Astra Tech AB, Mo lndal, Sweden.# Camlog, Camlog Biotechnologies, Wimsheim, Germany.** References 41, 45, 47, 55-58, and 63-72. References 41, 45, 47, 55, 58, 63, 65-68, 70, and 71. References 41, 45, 47, 55, 58, 63, 65-68, and 70-72.


1712


14/19

12 studies 41,45,47,55,58,63,65-68,70,71 out of 17 previ-ously selected (Table 3) were included in the meta-analysis (Table 3, last row, and Table 4; Fig. 3).Two studies 56,72 were excluded because they didnot include implants with lengths 8 mm, whereasthe other three studies 57,64,69 were excluded becauseall short and conventional implants survived; there-fore, the RR could not be estimated.

When short implants were dened as < 10 mm long,theaforementioned 12studies 41,45,47,55,58,63,65-68,70,71were included in the meta-analysis, and additionally,thestudy by StrietzelandReichart 72 wasalso includedbecause it reported data for short implants withlengths < 10 mm, thus providing a total of 13 studies(Table 3, last row, and Table 4; Fig. 3).

For both denitions of short implant length ( 8 and< 10 mm), no statistically signicant difference ( P =0.145 and 0.173, respectively) in survival was dem-onstrated between short and conventional rough-sur-face implants placed in partially edentulous patients(Table 4; Fig. 3).

DISCUSSIONSummary of Main Results In the present study, a systematic review and meta-analyses of prospective studies published in the den-tal literature in the English language were conductedto address the focused question Is there a signicantdifference in survival between short ( 8 or < 10 mm)and conventional ( 10 mm) rough-surface dental im-plants placed in 1) totally or 2) partially edentulouspatients? Meta-anaylses revealed that no statisti-cally signicant difference in survival existed betweenshort and conventional rough-surface implants in ei-ther totally or partially edentulous patients.

Overall Completeness, Quality, and Applicability of Evidence The selected studies fullled the objective of the re-view. However, certain types of patients as denedby exclusion criteria 2 through 4 were not taken intoaccount. In that respect, the selected cohorts ex-hibited a certain divergence from the general patientpopulation treated in everyday clinical practice. Theamount (number of selected studies, patients, andimplants) and quality (as revealed by the processof quality assessment) of evidence appears to allowrobust conclusions.

The results of the review seem to have signi-cant clinical implications. Hence, the placement of rough-surface short implants appears to be an efca-cious treatment modality for the replacement of miss-ing teeth in totally or partially edentulous patients.

Potential Biases in the Review Process The present systematic review applied a series of strategies in the search and selection of studies, aswell as data extraction and analyses, to prevent orminimize bias. An extensive manual search was un-dertaken because too many relevant articles con-tained survival data for short implants in their textand tables, but not in their title and abstract, and theonly way of retrieving those data was through a man-ual search. Contact with the authors of 125 articlesallowed the identication of relevant articles initiallynot depicted through electronic and manual searches

and the retrieval of a signicant amount of missing,unpublished, or unclear data in a form suitable forsubsequent meta-analysis (Tables 2 and 3). Becauseperiodontal pathogens may be transmitted from teethto implants in partially edentulous patients, and peri-odontal pockets may serve as reservoirs for bacterialcolonization around implants, 73 whereas in totallyedentulous patients such a transmission is not feasi-ble, it was deemed methodologically appropriate toperform separate meta-analyses, according to thetype of patient edentulism. This approach is also jus-tied by the difference between totally and partiallyedentulous patients with regard to the type of restora-tion placed (Tables 2 and 3). Furthermore, exclusioncriteria 2 through 4 aimed at preventing the introduc-tion of potential confounders and, therefore, system-atic bias (selection bias) into themeta-analyses.Froma statistical point of view, no signicant heterogeneityamong selected studies was revealed in the majorityof separate meta-analyses; furthermore, no evidence of publication bias existed.

However, specic limitations were also present.Survival risks were used asestimatesof actualsurvivalrates; therefore, the impact of total exposure time of each implant within the oral cavity upon implant sur-vival was not taken into account. Unfortunately, the

Figure 1.Funnel plot of the log RR versus its standard error calculated for selected studies (n = 13) reporting on short (length < 10 mm) versusconventional (length 10 mm) implants placed in partially edentulous

patients.


1713
http://www.joponline.org/action/showImage?doi=10.1902/jop.2009.090107&iName=master.img-000.png&w=239&h=160


15/19

calculation of actual implant survival rates could notbe carried out because, practically, it is too difcultor virtually impossible to record the total exposuretime of each and every implant included in the meta-analyses. Such a task would require complete accessto the raw data of all selected studies. Despite this lim-itation, it is of interest to note that favorable percent-ages of survival of short rough-surface implants(exceeding 95% and being comparable to those of conventional implants) have been reported byseven 41,42,47,49,58,67,68 of eight selected long-termstudies,withonlyonepossibleexception, 63 asdemon-strated in Tables 2 and 3, indicating the efcacy of short implant placement on a long-term basis.

Statistical analyses in this review were restricted toimplant-relatedsurvivaldata.Theuseofpatient-based

statistical analysis was hampered

by the lack of adequate patient-related survival data.

Agreements/Disagreements With Other Reviews The nding that no statisticallysignicant difference in survivalexisted between short andconven-tional rough-surface implants intotally or partially edentulous pa-tients is in agreement with previ-ous comprehensive reviews. 18,20

CONCLUSIONSWithin the limitations of the pres-ent systematic review, the follow-ing conclusions may be drawn.

General Conclusions/Strength of Evidence In general, the process of qualityassessment revealed the meth-

odologic quality of the studies included in the meta-analyses wassufcient. Thebodyof acquiredevidenceappears to be adequate to draw robust conclusions. Inthe majority of meta-analyses, no signicant hetero-geneity among selected studies was demonstrated,and no evidence of publication bias existed.

Specic Conclusion There is no signicant difference in survival betweenshort ( 8 or < 10 mm) and conventional ( 10 mm)rough-surface implants in totally or partially edentu-lous patients.

Implications for Clinical Practice Based on the ndings of the present article, it seemsreasonable to suggest that, in everyday clinicalpractice, clinicians can use short implants as an

Table 4.

Summary of Meta-Analyses Comparing Survival of Short Versus Conventional Implants

Studies

(n)

Pooled RR

(weighted mean [95% CI])

P Value

for RR

Heterogeneity

P Value

StatisticalModel

(method)Totally edentulous patients

L 8 mm versus L 10 mm 6 1.01 [0.97, 1.04] 0.978* 0.175 Fixed effectsL < 10 mm versus L 10 mm 6 0.99 [0.94, 1.06] 0.978* 0.036 Random effects

Partially edentulous patientsL 8 mm versus L 10 mm 12 0.99 [0.98, 1.00] 0.145* 0.919 Fixed effectsL < 10 mm versus L 10 mm 13 0.99 [0.98, 1.00] 0.173* 0.964 Fixed effects

CI = condence intervals; L = length.* No statistically signicant difference in primary outcome variable between short and conventional implants ( P > 0.05). No statistically signicant heterogeneity among studies ( P > 0.10).

Figure 2.Forest plot for selected studies reporting survival of short (length < 10 mm) versus conventional(length 10 mm) implants in totally edentulous patients. Weighted mean of RR and 95%condence intervals (CI). RR > 1 indicates higher survival for short compared to conventional implants.


1714


16/19

efcacious treatment modality for the replacement of missing teeth in totally and partially edentulous pa-tients whenever the placement of conventional im-plants is impossible or not preferable if advancedsurgical procedures would be concomitantly required.

Implications for Clinical Research/Systematic Reviews It is desirable that futurestudies report not only implant

survival, but also all parameters determining implantprognosis (such as peri-implant bleeding on probing,probing depth, clinical attachment level, and clinicaland radiographic marginal bone level) so that futuresystematic reviews will be able to compare short andconventional implants withregardto these parameters.

It is recommended to report implant survival datanot only in relation to implant length, but also crown-to-root ratio of implants.

ACKNOWLEDGMENTSThe following individualsare gratefully acknowledgedfor participating in the process of contact with authors:

Murray Arlin, Weston, Ontario; Kris-tina Arvidson, Bergen, Norway; PerAstrand, Umea , Sweden; CharlesBabbush, Lyndhurst, Ohio; WilliamBecker, Los Angeles, California; UrsBelser, Geneva, Switzerland; MichaelBornstein, Bern, Switzerland; Ge rardBrunel, Toulouse, France; DanielBuser, Bern, Switzerland; MatteoChiapasco, Milan, Italy; David Co-chran, San Antonio, Texas; DouglasDeporter, Toronto, Ontario; KarlDula, Bern, Switzerland; Steven Eck-ert, Rochester, Minnesota; Alf Eliasson, Orebro, Sweden; KerstinFischer, Falun, Sweden; ChristianFrei,Bern,Switzerland; Bertil Friberg,Gothenburg, Sweden; John Gonsol-

ley, Richmond, Virginia; Risto-PekkaHapponen, Turku, Finland; TorstenJemt, Gothenburg, Sweden; DiegoLops, Milan, Italy; Henry Meijer, Gro-ningen, The Netherlands; Youji Miya-moto, Tokushima, Japan; IgnaceNaert, Leuven, Belgium; Rabah Nedir,Vevey, Switzerland; Marc Quirynen,Leuven, Belgium; Gerry Raghoebar,Groningen, The Netherlands; MarioRoccuzzo, Turin, Italy; EugenioRomeo,Milan, Italy;Kees Stellingsma,

Groningen, The Netherlands; FrankPeter Strietzel, Berlin, Germany;GeorgesTawil,Beirut,Lebanon; Dam-ien Walmsley, Birmingham, United

Kingdom; Dietmar Weng, Starnberg, Germany; Go ranWidmark, Mo lndal, Sweden; Sheldon Winkler, Philadel-phia, Pennsylvania; Daniel Wismeijer, Amsterdam, TheNetherlands; Chris Wyatt, Vancouver, BritishColumbia;andRolandYounan,Beirut,Lebanon.Theauthorsreportno conicts of interest related to this review.

REFERENCES1. Bra nemark PI, Hansson BO, Adell R, et al. Osseointe-

grated implants in the treatment of the edentulous jaw.Experience from a 10-year period. Scand J Plast Reconstr Surg Suppl 1977;16:1-132.

2. Adell R, Lekholm U, Rockler B, Bra nemark PI. A 15-year study of osseointegrated implants in the treat-ment of the edentulous jaw. Int J Oral Surg 1981;10:387-416.

3. Jemt T. Modied single and short-span restorationssupported by osseointegrated xtures in the partiallyedentulous jaw. J Prosthet Dent 1986;55:243-247.

4. Bragger U, Hammerle C, Weber HP. Fixed reconstruc-tions in partially edentulous patients using two-part ITIimplants (Bonet) as abutments. Treatment planning,

Figure 3.Forest plot for selected studies reporting survival of short (length < 10 mm) versus conventional(length 10 mm) implants in partially edentulous patients. Weighted mean of RR and 95%

condence intervals (CI). RR > 1 indicates higher survival for short compared to conventionalimplants.


1715


17/19

indications and prosthetic aspects. Clin Oral Implants Res 1990;1:41-49.

5. Berglundh T, Persson L, Klinge B. A systematic reviewof the incidence of biological and technical complica-tions in implant dentistry reported in prospective lon-gitudinal studies of at least 5 years. J Clin Periodontol 2002;29(Suppl. 3):197-212.

6. Lang NP, Pjetursson BE, Tan K, Bragger U, Egger M,Zwahlen M. A systematic review of the survival andcomplication rates of xed partial dentures (FPDs)after an observation period of at least 5 years. II.Combined toothimplant-supported FPDs. Clin Oral Implants Res 2004;15:643-653.

7. Pjetursson BE, Tan K, Lang NP, Bra gger U, Egger M,Zwahlen M. A systematic review of the survival andcomplication rates of xed partial dentures (FPDs)after an observation period of at least 5 years. I.Implant-supported FPDs. Clin Oral Implants Res 2004;15:625-642.

8. Pjetursson BE, Bra gger U, Lang NP, Zwahlen M.Comparison of survival and complication rates of

tooth-supported xed dental prostheses (FPDs) andimplant-supported FPDs and single crowns (SCs). Clin Oral Implants Res 2007;18(Suppl. 3):97-113.

9. Jung RE, Pjetursson BE, Glauser R, Zembic A, ZwahlenM, Lang NP. A systematic review of the 5-year survivaland complication rates of implant-supported singlecrowns. Clin Oral Implants Res 2008;19:119-130.

10. Adell R, Lekholm U, Bra nemark PI. Surgical proce-dures. In: Bra nemark PI, Zarb GA, Albrektsson T.Tissue Integrated Prostheses: Osseointegration in Clin- ical Dentistry . Chicago: Quintessence Publishing;1985:211-232.

11. Lee JH, Frias V, Lee KW, Wright RF. Effect of implantsize and shape on implant success rates: A literaturereview. J Prosthet Dent 2005;94:377-381.

12. Chiapasco M, Zaniboni M, Boisco M. Augmentationprocedures for the rehabilitation of decient edentu-lous ridges with oral implants. Clin Oral Implants Res 2006;17(Suppl. 2):136-159.

13. Donos N, Mardas N, Chadha V. Clinical outcomesof implants following lateral bone augmentation:Systematic assessment of available options (barriermembranes, bone grafts, split osteotomy). J Clin Peri- odontol 2008;35(Suppl. 8):173-202.

14. Pjetursson BE, Tan WC, Zwahlen M, Lang NP. Asystematic review of the success of sinus oor eleva-tion and survival of implants inserted in combinationwith sinus oor elevation: Part I: Lateral approach.J Clin Periodontol 2008;35(Suppl. 8):216-240.

15. Rocchietta I, Fontana F, Simion M. Clinical outcomesof vertical bone augmentation to enable dental implantplacement: A systematic review. J Clin Periodontol 2008;35(Suppl. 8):203-215.

16. Tan WC, Lang NP, Zwahlen M, Pjetursson BE. Asystematic review of the success of sinus oor elevationand survival of implants inserted in combination withsinus oor elevation. Part II: Transalveolar technique.J Clin Periodontol 2008;35(Suppl. 8):241-254.

17. Tonetti MS, Ha mmerle CH. Advances in bone aug-mentation to enable dental implant placement: Con-sensus Report of the Sixth European Workshop onPeriodontology. J Clin Periodontol 2008;35(Suppl. 8):168-172.

18. Hagi D, Deporter DA, Pilliar RM, Arenovich T. Atargeted review of study outcomes with short ( 7 mm)

endosseous dental implants placed in partially eden-tulous patients. J Periodontol 2004;75:798-804.

19. das Neves FD, Fones D, Bernardes SR, do Prado CJ,Neto AJ. Short implantsAn analysis of longitudinalstudies. Int J Oral Maxillofac Implants 2006;21:86-93.

20. Renouard F, Nisand D. Impact of implant length anddiameter on survival rates. Clin Oral Implants Res

2006;17(Suppl. 2):35-51.21. ten Bruggenkate CM, Asikainen P, Foitzik C, KrekelerG, Sutter F. Short (6 mm) nonsubmerged dentalimplants: Results of a multi-center clinical trial of 1 to 7 years. Int J Oral Maxillofac Implants 1998;13:791-798.

22. Schou S, Holmstrup P, Worthington HV, Esposito M.Outcome of implant therapy in patients with previoustooth loss due to periodontitis. Clin Oral Implants Res 2006;17(Suppl. 2):104-123.

23. Esposito M, Coulthard P, Thomsen P, Worthington HV.Enamel matrix derivative for periodontal tissue regen-eration in treatment of intrabony defects: A Cochranesystematic review. J Dent Educ 2004;68:834-844.

24. Esposito M, Grusovin MG, Coulthard P, Thomsen P,Worthington HV. A 5-year follow-up comparativeanalysis of the efcacy of various osseointegrateddental implant systems: A systematic review of ran-domized controlled clinical trials. Int J Oral Maxillofac Implants 2005;20:557-568.

25. Esposito M, Coulthard P, Worthington HV, Jokstad A.Quality assessment of randomized controlled trials of oral implants. Int J Oral Maxillofac Implants 2001;16:783-792.

26. Roccuzzo M, Bunino M, Needleman I, Sanz M. Peri-odontal plastic surgery for treatment of localized gingi-val recessions: A systematic review. J Clin Periodontol 2002;29(Suppl. 3):178-194.

27. Kotsovilis S, Karoussis IK, Trianti M, Fourmousis I.

Therapy of peri-implantitis: A systematic review.J Clin Periodontol 2008;35:621-629.28. Cohen J. A coefcient of agreement for nominal

scales. Educ Psychol Meas 1960;20:37-46.29. Landis JR, Koch GG. The measurement of observer

agreement for categorical data. Biometrics 1977;33:159-174.

30. Fleiss JL, Chilton NW. The measurement of interexa-miner agreement on periodontal disease. J Periodontal Res 1983;18:601-606.

31. Sim J, Wright CC. The kappa statistic in reliabilitystudies: Use, interpretation, and sample size require-ments. Phys Ther 2005;85:257-268.

32. Begg CB, Mazumdar M. Operating characteristics of arank correlation test for publication bias. Biometrics

1994;50:1088-1101.33. Egger M, Davey SG, Schneider M, Minder C. Bias inmeta-analysis detected by a simple, graphical test. Br Med J 1997;315:629-634.

34. Gart JJ, Zweifel JR. On the bias of various estimatorsof the logit and its variance with application to quantalbioassay. Biometrika 1967;54:181-187.

35. Fleiss JL. Statistical Methods for Rates and Propor- tions , 2nd ed. New York: John Wiley; 1981:61-67.

36. Geertman ME, Boerrigter EM, Van Waas MA, van OortRP. Clinical aspects of a multicenter clinical trial of implant-retained mandibular overdentures in patientswith severely resorbed mandibles. J Prosthet Dent 1996;75:194-204.

37. Boerrigter EM, Geertman ME, Van Oort RP, et al.Patient satisfaction with implant-retained mandibular


1716


18/19

overdentures. A comparison with new complete den-tures not retained by implants-a multicentre random-ized clinical trial. Br J Oral Maxillofac Surg 1995;33:282-288.

38. Kwakman JM, Voorsmit RA, Freihofer HP, Van WaasMA, Geertman ME. Randomized prospective clinicaltrial of two implant systems for overdenture treatment:

A comparison of the 2-year and 5-year results usingthe clinical implant performance scale. Int J Oral Maxillofac Surg 1998;27:94-98.

39. Walmsley AD, Frame JW. Implant supported over-dentures The Birmingham experience. J Dent 1997;25(Suppl. 1):S43-S47.

40. Walmsley AD, Brady CL, Smith PL, Frame JW. Mag-net retained overdentures using the Astra dental im-plant system. Br Dent J 1993;174:399-404.

41. Brocard D, Barthet P, Baysse E, et al. A multicenterreport on 1022 consecutively placed ITI implants: A 7-year longitudinal study. Int J Oral Maxillofac Implants 2000;15:691-700.

42. Meijer HJ, Raghoebar GM, Vant Hof MA, Visser A. Acontrolled clinical trial of implant-retained mandibularoverdentures: 10 years results of clinical aspects andaftercare of IMZ implants and Bra nemark implants.Clin Oral Implants Res 2004;15:421-427.

43. Stellingsma K, Raghoebar GM, Meijer HJ, Stegenga B.The extremely resorbed mandible: A comparativeprospective study of 2-year results with 3 treatmentstrategies. Int J Oral Maxillofac Implants 2004;19:563-577.

44. Stellingsma K, Bouma J, Stegenga B, Meijer HJ,Raghoebar GM. Satisfaction and psychosocial aspectsof patients with an extremely resorbed mandibletreated with implant-retained overdentures. A pro-spective, comparative study. Clin Oral Implants Res 2003;14:166-172.

45. Fischer K, Stenberg T. Three-year data from a ran-domized, controlled study of early loading of single-stage dental implants supporting maxillary full-archprostheses. Int J Oral Maxillofac Implants 2006;21:245-252.

46. Fischer K, Stenberg T. Early loading of ITI implantssupporting a maxillary full-arch prosthesis: 1-yeardata of a prospective, randomized study. Int J Oral Maxillofac Implants 2004;19:374-381.

47. Romeo E, Ghisol M, Rozza R, Chiapasco M, Lops D.Short (8-mm) dental implants in the rehabilitation of partial and complete edentulism: A 3- to 14-yearlongitudinal study. Int J Prosthodont 2006;19:586-592.

48. Romeo E, Lops D, Margutti E, Ghisol M, Chiapasco

M, Vogel G. Long-term survival and success of oralimplants in the treatment of full and partial arches: A7-year prospective study with the ITI Dental ImplantSystem. Int J Oral Maxillofac Implants 2004;19:247-259.

49. Stoker GT, Wismeijer D, van Waas MA. An eight-yearfollow-up to a randomized clinical trial of aftercare andcost-analysis with three types of mandibular implant-retained overdentures. J Dent Res 2007;86:276-280.

50. Wismeijer D. A prospective study considering thecosts, aftercare and efciency in three different treat-ment modalities for mandibular overdentures on ITI-dental implants in edentulous patients. In: WismeijerD. The Breda Implant Overdenture Study. [Thesis].Amsterdam: Proefschrift Vrije Universiteit Amsterdam;1996:129-151.

51. Wismeijer D, van Waas MA, Vermeeren JI, Kalk W.Patients perception of sensory disturbances of themental nerve before and after implant surgery: Aprospective study of 110 patients. Br J Oral Maxillofac Surg 1997;35:254-259.

52. Wismeijer D, van Waas MA, Vermeeren JI, Mulder J,Kalk W. Patient satisfaction with implant-supported

mandibular overdentures. A comparison of three treat-ment strategies with ITI-dental implants. Int J Oral Maxillofac Surg 1997;26:263-267.

53. Wismeijer D, van Waas MA, Mulder J, Vermeeren JI,Kalk W. Clinical and radiological results of patientstreated with three treatment modalities for overden-tures on implants of the ITI Dental Implant System. Arandomized controlled clinical trial. Clin Oral Implants Res 1999;10:297-306.

54. Timmerman R, Stoker GT, Wismeijer D, Oosterveld P,Vermeeren JI, van Waas MA. An eight-year follow-upto a randomized clinical trial of participant satisfactionwith three types of mandibular implant-retained over-dentures. J Dent Res 2004;83:630-633.

55. Buchs AU, Hahn J, Vassos DM. Efcacy of threadedhydroxyapatite-coated implants placed in the poste-rior mandible in support of xed prostheses. Implant Dent 1996;5:106-110.

56. Deporter DA, Todescan R, Watson PA, Pharoah M,Levy D, Nardini K. Use of the Endopore dental implantto restore single teeth in the maxilla: Protocol andearly results. Int J Oral Maxillofac Implants 1998;13:263-272.

57. van Steenberghe D, De Mars G, Quirynen M, Jacobs R,Naert I. A prospective split-mouth comparative studyof two screw-shaped self-tapping pure titanium im-plant systems. Clin Oral Implants Res 2000;11:202-209.

58. Deporter DA, Todescan R, Watson PA, Pharoah M,

Pilliar RM, Tomlinson G. A prospective human clinicaltrial of Endopore dental implants in restoring thepartially edentulous maxilla using xed prostheses.Int J Oral Maxillofac Implants 2001;16:527-536.

59. Deporter DA, Todescan R, Nardini K. Use of a tapered,porous-surfaced dental implant in combination withosteotomes to restore edentulism in the difcult max-illa. Implant Dent 1999;8:233-240.

60. Deporter D, Todescan R, Caudry S. Simplifying man-agement of the posterior maxilla using short, porous-surfaced dental implants and simultaneous indirectsinus elevation. Int J Periodontics Restorative Dent 2000;20:476-485.

61. Deporter D, Todescan R, Riley N. Porous-surfaceddental implants in the partially edentulous maxilla:

Assessment for subclinical mobility. Int J Periodontics Restorative Dent 2002;22:184-192.62. Rokni S, Todescan R, Watson P, Pharoah M, Adegbembo

AO, Deporter D. An assessment of crown-to-rootratios with short sintered porous-surfaced implantssupporting prostheses in partially edentulous patients.Int J Oral Maxillofac Implants 2005;20:69-76.

63. Mericske-Stern R, Gru tter L, Ro sch R, Mericske E.Clinical evaluation and prosthetic complications of single tooth replacements by non-submerged im-plants. Clin Oral Implants Res 2001;12:309-318.

64. Roccuzzo M, Bunino M, Prioglio F, Bianchi SD. Earlyloading of sandblasted and acid-etched (SLA) im-plants: A prospective split-mouth comparative study.One-year results. Clin Oral Implants Res 2001;12:572-578.


1717


19/19

65. Cochran DL, Buser D, ten Bruggenkate CM, et al. Theuse of reduced healing times on ITI implants with asandblasted and acid-etched (SLA) surface: Earlyresults from clinical trials on ITI SLA implants. Clin Oral Implants Res 2002;13:144-153.

66. Roccuzzo M, Wilson TG. A prospective study evaluat-ing a protocol for 6 weeks loading of SLA implants in

the posterior maxilla. One-year results. Clin Oral Implants Res 2002;13:502-507.67. Romeo E, Chiapasco M, Ghisol M, Vogel G. Long-

term clinical effectiveness of oral implants in thetreatment of partial edentulism. Seven-year life tableanalysis of a prospective study with ITI Dental Im-plants System used for single-tooth restorations. Clin Oral Implants Res 2002;13:133-143.

68. Romeo E, Lops D, Margutti E, Ghisol M, Chiapasco M,Vogel G. Implant-supported xed cantilever prosthesesin partially edentulous arches. A seven-year prospec-tive study. Clin Oral Implants Res 2003;14:303-311.

69. Frei C, Buser D, Dula K. Study on the necessity forcross-section imaging of the posterior mandible fortreatment planning of standard cases in implant den-tistry. Clin Oral Implants Res 2004;15:490-497.

70. Bornstein MM, Schmid B, Belser UC, Lussi A, Buser D.Early loading of non-submerged titanium implantswith a sandblasted and acid-etched surface: 5-year

results of a prospective study in partially edentulouspatients. Clin Oral Implants Res 2005;16:631-638.

71. Chiapasco M, Ferrini F, Casentini P, Accardi S,Zaniboni M. Dental implants placed in expanded nar-row edentulous ridges with the Extension Crest device.A 1-3-year multicenter follow-up study. Clin Oral Implants Res 2006;17:265-272.

72. Strietzel FP, Reichart PA. Oral rehabilitation usingCamlog screw-cylinder implants with a particle-blasted and acid-etched microstructured surface.Results from a prospective study with special consid-eration of short implants. Clin Oral Implants Res 2007;18:591-600.

73. Heydenrijk K, Meijer HJ, van der Reijden WA,Raghoebar GM, Vissink A, Stegenga B. Microbiotaaround root-form endosseous implants: A review of the literature. Int J Oral Maxillofac Implants 2002;17:829-838.

Correspondence: Dr. Ioannis Fourmousis, Department of Periodontology, School of Dentistry, University of Athens,Thivon St. 2, GR 11527, Athens, Greece. Fax: 30-210-7461202; e-mail: [email protected].

Submitted February 19, 2009; accepted for publicationMay 20, 2009.


Date post:	04-Jun-2018
Category:	Documents
Upload:	amar-bhochhibhoya
View:	216 times
Download:	0 times

Effect of Length and Implant Surface

Documents