Timing of Dental Implant Loading-Hary Silvasan

06 I

I research _ dental implant loading

Fig. 1_Direct loading at placementand delayed loading after bone

healing. Fig. 2_Conventional implant protocol

without any loading performing theprosthetic in part after bone healing

(e.g. Brnemark protocol).

implants3_2010

_Osseointegration is the process by which livingbone attaches to the artificial surface of an implant bythe formation of bony tissue without growth of fi-brous tissue at the bone-implant interface.

_Introduction

Osseointegration is a highly dynamic process, whichdoes not only address the formation of bone onto animplant surface after it has been placed, but it also ad-dresses the remodelling or maintenance of bone dur-ing the life of the implant.

The long term success of an implant treatment istheoretically determined by factors related to the pa-

tient, the implant components and the treating clini-cians.1 Before the introduction of the Prof. Brnemarkprotocol, dental implants were commonly loaded atplacement because immediate bone stimulation wasconsidered to avoid crestal bone loss (Fig.1).2 The cli-nician is often faced with the challenge of identifyingthe successful osseointegration of implant. Clinicalsuccess is often determined by a lack of mobility andability of the implant to resist functional loading.3

Radiographically, bone should appear to be closelyapposed to the implant surface. The current achiev-able resolution obtained in medical imaging, how-ever, is about 10 times less than what is required to ob-serve a soft tissue cell. Therefore, radiographic as-sessment alone is unsuitable to determine with cer-tainty if a soft tissue layer is present. When an implantis exposed to excessive micromotion at the bone-im-plant interface during healing, fibrous tissue encap-sulation of the implant rather than osseointegrationmay occur. Conventional implant protocols havebeen based on the achievement of primary stabilityand prolonged non-loaded healing periods (Fig. 2).4

That was achieved by a two stage technique andan unloaded healing period of three to six months.Delayed implant loading was empirically based on thebelief that the transfer of any micromotion to the im-plant surface during healing would result in fibrousencapsulation rather than osseointegration. A per-ceived psychological, economical and functional ad-vantage of shortened treatment periods has encour-aged clinicians to challenge this convention with im-mediate temporization (Fig. 3) and/or the early andimmediate loading of dental implants.

The relative merits of these shortened loading pro-tocols will be discussed with respect to their biologi-

Timing of dental implant loadingA Literature ReviewAuthor_Dr Marius Hary Silvasan, Romania

Fig. 1

Fig. 2

I 07

research _ dental implant loading I

implants3_2010

cal implication, the current evidence based literatureand the factors that might influence their outcomes.There is a growing body of published literature sup-porting reduced implant loading times. Abutmentconnection and placement of a restoration in occlu-sion with the opposing dentition of an implant at thetime of surgery or within 48 hours of placement is re-ferred to as immediate loading The functionalrestoration of an implant from 48 hours up to 3months after placement has been defined as earlyloading.5 Both the immediate and early functionalloading of implants before lamellar bone formationcarry an inherent biological risk. Shortened loadingprotocols may expose the healing bone to implant in-terface to mechanical overload as described in WollfsLaw and Frosts Mechanostat theory (Fig. 4).

Interfacial micromotion above the biologicalthreshold can result in the subsequent loss of implantstability. Rough titanium surfaces offer better im-plant anchorage in bone and more rapid bone depo-sition.6 The general applicability of these principleswill be considered as to their biological implications,the current evidence base and the factors that influ-ence their results.

_Materials and Methods

Clinical reports on dental implants found in majorscientific journals and through searching in PUBMED, QUINTESSENZ and MED-LINE, have served asthe basis for this review. The following search terms,alone or in combination, were used: implant loading,immediate loading, early loading, delayed loading.After screening the titles and abstracts for possiblerelevance, they were ordered in full text. We alsoscreened reference list of publications and relevantsystematic reviews. To minimise bias, only RCTs of os-seointegrated dental implants were considered. To beincluded, RCTs had to compare the same osseointe-grated implants loaded at different times for a periodof at least 12 months of loading.

For the purpose of this review immediate loadingwas defined as an implant put in function within 48hours after its placement; early loading as those im-plants put in function from 48 hours up to 3 monthsafter placement, and conventional loading as thoseimplants put in function between 3 to 6 months afterinsertion. Implant mobility and removal of stable im-plants dictated by progressive marginal bone loss orinfection have been assessed. Implant mobility of in-dividual implants could be assessed manually or withdevices such as Periotest (Siemens, Munich, Ger-many) or Resonance frequencyAnalysisOsstell(Integration diagnostics, Gteborg, Sweden). In oursearch we aimed at including randomized controlledtrials. Most clinical reports were on a few implant sys-

tems only and threaded commercially pure titaniumimplants ad modum Brnemark dominated the liter-ature. The quality assessment of the included trialswas undertaken independently. The following qualitycriteria were examined:

Allocation concealment was recorded as ade-quate ( A ), unclear ( B ), or inadequate (C), as describedelsewhere [Higgins, Green S. Handbook for systematicreviews of interventions].

Allocation concealment was considered adequateif it was centralized (e.g. Allocation by a central officeunaware of subject characteristics). If randomizationwas pharmacy controlled; if prenumbered or codedidentical containers were administered serially toparticipants.

A score of A was recorded if there was a clear ex-planation for a withdrawals or dropouts in each treat-ment group or if there were no dropouts. If clear ex-planation for any dropouts were given, the risk of biasof the assessment of reasons for dropping out wasevaluated. A strong scientific basis is required aswell. A score of B was recorded if clear explanationsfor any dropouts or withdrawals were not provided.Articles or authors that stated that allocation con-cealment procedures were implemented but did notprovide details on how this was accomplished werecoded as unclear. A score of C was recorded if there

Fig. 3_Immediate temporization anddelayed loading.Fig.4_Loading zones acc. to H. M. Frost

Fig. 3

Fig. 4

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implants3_2010

were insufficient scientific basis or any procedurethat was entirely transparent before allocation, suchas an open list of random numbers. Hence, after athorough reading of the studies included in this re-view, one of these scores has been qualified accord-ing to accuracy and the underlying scientific bases.

_Results

In 2002, a consensus meeting was convenedwithin the World Congress organized by the SpanishBoard of Implantology in Barcelona.5 There was anagreement on terminology for the timing of loading(immediate, early, delayed) and for the implant load-ing (occlusal loading and nonocclusal loading). Ac-cording to this consensus meeting the following ter-minology was described:

Immediate loadingThe prosthesis is attached to the implants the same

day the implants are placed

Early loadingThe prosthesis is attached at a second procedure,

earlier than the conventional healing period of 3 to 6months. The time of loading is started after somedays/weeks.

Delayed loadingThe prosthesis is attached at a second procedure

after a conventional healing period of 3 to 6 months.

Occlusal loadingThe crown/bridge is in contact with the opposing

dentition in centric occlusion.

Nonocclusal loadingThe crown/ bridge is not in contact in centric oc-

clusion with the opposing dentition in natural jaw po-sition.

The available literature demonstrates the possibil-ity of achieving good results with different protocols,especially with immediate loading protocol, at least ingood-quality bone, which supports the idea thatthese concepts may serve as a viable option in implantdentistry. However, the prerequisites for achievingand maintaining acceptable results and the limita-tions of immediate/early loading are not fully known.Moreover, the terminology used in these protocols isconfusing since the difference between different pro-tocols is not well defined, and publication titles cantherefore be very misleading. Of 26 potential studies,7 have been excluded because of insufficient patientselection data or prothesis loading longer than oneday (immediate loading), not corresponding to theBarcelona consensus, and 5 have been excluded sincethe follow up was shorter than 12 months. Fourteen

studies have been introduced in this review, the con-clusions having been discussed on their basis.

The majority of the studies considered in this re-view registered a relatively short follow up. In 6 stud-ies the follow up covered a period longer than 24months.

Daniel Sullivan, Giampaolo Vicenzi, Sylvan Feld-man performed a multicenter study: the performanceof Osseotite implants after an 1 stage surgery and ab-breviated healing period of 2 months in 10 privatepractice centers. 142 patients, partially or completelyedentulous, enrolled in this early loading study, re-ceived 526 implants, 65.4 % in mandible and 34.6 %in maxilla. Implants were loaded after a healing periodof about two months. The distribution of the prosthe-sis types included 118 single tooth restoration (118implants), 134 short-span prosthesis (327 implants)and 16 long-span restoration (81 implants).

Eight of the eleven implant failures occurred dur-ing nonsubmerged healing prior to prosthetic load-ing. Provisional restoration was placed at 2.1 0.5months, at which time implants were evaluated formobility, gingival health and radiolucency. The cumu-lative success rate of these 526 implants was 97.9 %at 5 years.

These results suggest that success can be expectedwith Osseotite implants after a nonsubmerged re-duced healing period of two months in this patientpopulation.7

Par-lov stman, Mats Hellman, Lars Sennerbyevaluated in a prospective clinical study the radi-ographic and clinical outcome of immediately load-ing implants in the partial edentulous mandible overa 4 year follow up period.

96 patients were evaluated and 77 patients whomet the inclusion criteria were included. A total of 111fixed partial dentures supported by 257 BrnemarkSystem implants (77 turned and 180 Ti Unite im-plants) was delivered. Four (1.16 %) of the 257 im-plants did not osseointegrate after 4 years. Threeturned implants (3.9 %) and one oxidized implant (0.6 %) failed after 4 to 13 months. Immediate load-ing of implants with firm primary stability in partiallyedentulous areas of the mandible appears to be a vi-able procedure with predictable outcome.8

Richard P. Kinsel, Mindy Liss evaluated in a retro-spective study the effects of implants dimensions,surface treatment, location in the dental arch, num-bers of supporting implant abutments, surgical tech-nique, and generally recognized risk factors on thesurvival of a series of single stage Straumann dental

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implants3_2010

implants, placed into edentulous arches using an im-mediate loading protocol. Data were collected for 344single-stage implants placed into 56 edentulousarches (39 maxillae and 17 mandibles ) of 43 patientsand immediate loaded with a one piece provisionalfixed prosthesis.

Each patient received between 4 and 18 implantsin one or both dental arches. Periapical radiographswere obtained over a 2 to 10 year follow up period toevaluate crestal bone loss following insertion of thedefinitive metal-ceramic fixed prostheses. A total of16 implants failed to successfully integrate. Increasedrates of failure were associated with reduced implantlength, placement in the posterior region of the jaw,increased implant diameter and surface treatment.Implant length emerged as the sole significant pre-dictor of implant failure.

In this prospective analysis, in 56 consecutivelytreated edentulous arches with multiple single stagedental implants loaded immediately, reduced implantlength was the sole significant predictor of failure.9

George Romanos, Georg Hubertus Nentwig evalu-ated immediate loading of oral implants on heavysmokers. Nine patients (5 male and 4 female) with amean age of 52.4 8.3 years who smoked more than2 packs a day for more than 10 years (heavy smokers)were included in this prospective clinical study. Sev-enty two implants, 6 implants in each jaw, 6 maxillaeand 6 mandibles, made from comercially pure tita-nium (grade 2), with a progressive thread design andsandblasted surface (Ankylos, Friadent) were used.Provisional fixed prostheses had centric occlusal con-tacts and group function in the lateral movements ofthe mandible (immediate occlusal loading). Clinicaland radiographic indices were evaluated at the startof loading and at 3 month intervals after loading. After a mean loading period of 33.7 19.0 months(range 6 to 66 months) one implant was mobile. Allclinical indices had values in normal ranges. The Peri-otest values decreased with time, indicated increasedsecurity of implants in bone. Crestal bone loss wasstable, with only two sites presented minimal verticalbone loss and six presented minimal horizontal boneloss. This study showed that immediate loading of oralimplants may be successful in heavy smokers undersome circumstances.10 Gioacchino Cannizzaro,Michele Leone,Ugo Con Solo, Vittorio Ferri, Marco Es-posito compared the efficacy of immediae function-ally loaded implants placed with a flapless procedure(test group) versus implants placed after flap eleva-tion and conventional load-free healing (controlgroup) in partially edentulous patients. Forty patientswere randomized: 20 to the flapless immediateloaded group and 20 to the conventional group. Im-plants in the immediately loaded group were providedwith full acrylic resin temporary restoration in the

same day. Implants in the conventional group weresubmerged (anterior region) or left unsubmerged(posterior region) and left load-free for 3 months(mandibles) or 4 months (maxillae). 52 implants wereplaced in the in the flapless group and 56 in the con-ventionally group. After three years no dropouts orfailures occurred.

When comparing baseline data with those at theyears 1, 2, and 3 within each group, mean Osstell val-ues of the flapless group did not increase, whereasthere were statistically significant increases in the Periotest values.

Implants can be successfully placed flapless andloaded immediately without compromising successrates; the procedure decreases treatment time andpatient discomfort.11

Roberto Crespi, Paolo Cappare, Enricho Gherlone,George E. Romanos performed a study to report aclinical comparative assessement of crestal bone levelchange around single implants in fresh extractionsockets in the esthetic zone of the maxilla either im-mediately loaded or loaded after a delay. Forty pa-tients were included in a prospective, randomizedstudy. All patient required 1 tooth extraction. Im-plants were positioned immediately after tooth ex-traction and were loaded immediately in the testgroup (20 implants) and after 3 months in the controlgroup (20 implants). All implants were 13 mm long.Thirty implants had a diameter of 5 mm, and 10 had adiameter of 3.75 mm. Radiographic examination wasmade at baseline, at 6 months and at 24 months. Af-ter a 24-month follow up period, a cumulative sur-vival rate of 100 % was reported for all implants. Thesuccess rate and radiographic results of immediaterestorations of dental implants placed in fresh ex-traction sockets were comparable to those obtainedin delayed loading group.12 Two studies registered a18 month follow up. Joseph Nissan, George E. Ro-manos, Ofer Mardinger, Gavriel Chaushu assessed theclinical effectiveness of immediate nonfunctionalloading for single tooth implants placed in the ante-rior maxilla following augmentation with cancellousfreeze-dried block graft, with clinical outcomes up to18 months after placement. Implants were immedi-ately restored with unsplinted acrylic resin provi-sional crowns. Eleven patients received 12 implants inthe anterior maxilla, and intraorally radiographs wereobtained immediate after implant placement and at6, 12 and 18 months. Survival rate and radiographicmarginal bone loss were evaluated at 0, 6, 12 and 18months. Marginal bone loss did not extend beyondthe first thread up to a 18 month follow-up.

Within the limits of this study, immediate non-functional loading for single-tooth implants placed

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implants3_2010

in the anterior maxilla following augmentation withcancellous freeze-dried block graft seems a promis-ing treatment alternative.13

Roberto Crespi, Paolo Cappare, Enricho Gherlone,George E. Romanos evaluated the clinical and radi-ographic outcome of dental implants immediateplaced and loaded into fresh extraction sockets after18 months. Twenty-seven patients, 15 women and 12men, received a total of 160 implants. 150 were placedimmediately after extraction.The sockets in the study

had fully preserved walls, and 10 were placed inhealed sites. Immediately after surgical procedure, allpatients received the temporary prosthetic recon-struction in occlusion. Five months post surgery, de-finitive metal-ceramic restorations were cementedon abutments. Intraoral digital radiographic exami-nation were performed 3 and 18 months after implantplacement. Mean marginal bone loss 18 months afterimmediate loading was 0.65 0.58 mm to the mesialside and 0.84 0.69 to the distal side in the maxillaand 1.13 0.51 mm mesially and 1.24 0.60 distally

Load time Splinttime

Sit. Impl.type

Followup

No.of pac. No.of impl.

Succ.rate

Reference Lev. of evid

Immediateloading

1 Day Ed.mand.

NovumBrnemark

12 Months 10 pac.30 impl.

86.7 % Els De Smetet al.

B

Immediateloading

1 Day Max.esthetic zone

Sweden &Martina


100 % Roberto Crespiet al.

C

Immediateloading

< 1 Day Part. ed.mand.

Ti UniteBrnemark


98.4% Rar-OslovOstman et al.

B

Immediateloading

< 1 Day Ed. max.Ed. mandib.

AnkylosFriadent

1260Months

9 pac.72 impl.

98.6 % George Romanos et al.

B

Immediateloading

1 Day Part.Edent.

ZimmerSwiss Plus


100 % GioacchinoCannizzaro et al.

B

Immediateloading

1 Day Ed. max. 39Ed. man. 17

Straumann 210Years

56 pac.344 impl.

95.6 % Richard P.Kinsel et al.

B

Immediateloading

1 Day Ant.maxila

3 I -9 impl.Zimmer-3 impl


100 % Joseph Nissanet al.

B

Immediateloading

< 1 Day All Edent.

Bicon 12 Months 209 pac.477 impl.

90.3 % Mohamed S.Erakat et al.

B

Immediateloading

< 1 Day Lat ed.mand.

Straumann 12 Months 20 pac.40 impl.

97.5 % Roberto Cornelini et al.

B

Immediateloading

< 1 Day Ed. max.part.

Sweden &Martina

18 Months 27 pac.160 impl.(150 after extr.)

100 % Roberto Crespiet al.

C

Immediateloading

< 1 Day Ed. max. ZimmerSwiss Plus



B

Immediateloading

< 1 Day Ed. max. Various 60 Months 44 pac.338 impl.

99.1 % Degidi et al. B

Immediateloading

1 Day Ed. mandib. Straumann 24 Months 9 pac.36 impl.

100 % PedroTortamano et al.

C

Tab. 1_Summarized data from thestudies /approaches used in this re-view with reference to immediateloading.

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implants3_2010

in the mandible. Within the limits of this clinical study,the results indicate that immediate loading of im-plants placed in immediate extraction sites can becarried out successfully.14 Six studies covered a 12month follow up. Els de Smet, Joke Duyck, JosvanderSloten, Ignace Naert performed a clinical trial to re-port on the implant outcome of delayed, early and immediate loading of implants in the edentulousmandible. On a consecutive basis, the first ten patientsreceived an overdenture retained by 2 ball attach-ments four months after implant insertion (delayed),and the next 10 patients received an overdentureone week after implant surgery (early). The next tenpatients were treated with a fixed prosthesis on 3implants (Brnemark, Novum) either the day of orthe day after surgery (immediate). All patients werefollowed for one year, half were followed for twoyears. One patient in each OD group lost both im-plants.

The losses occurred six months after loading in thedelayed group and one month after loading in theearly group. In the immediate group, one patient lostboth distal implants five months after loading. In twoother patients, one distal implant failed after one yearof loading. Maximal bite forces increased over timefor all groups. Marginal bone loss was the highest forthe immediate group.

According to this prospective controlled clinicaltrial, the results achieved with early implant loadingwere comparable to those achieved with implantsloaded after a delay. Distal implants are at higher riskfor failure in the immediate loading protocol.15 PedroTortamano, Tadashi Carlos Orii, Julio Yamanochi, At-las Edson Moleros Nakame, Tatiana de CarvalhoGuarnieri presented a new method for fabricating ef-fective definitive prostheses to immediate load im-plants in edentulous patients.Nine patients receivedfour implants each, and resin metal prostheses wereinstalled less than 48 hours after implant placement.Clinical evaluation of soft peri implant tissues wasconducted monthly after the sutures were removed,and radiographs were obtained 6, 12 and 24 monthsafter the surgery. The periotest revealed statisticalvalues that were stable, with no mobility. No signs ofinflammation and/or bleeding were observed.The ra-diographs did not reveal any continuous areas of ra-diolucency beyond the first thread of the 36 implantsafter 24 months.

Under immediate load, osseointegration of im-plants is possible, and the method for the fabricationof resin-metal prostheses has been reliable and pre-dictable.16 Giuseppe Luongo, Rosario Di Raimondo,Paolo Filippini, Federico Gualini, Cesare Paoleschievaluated the concept of an immediate loading pro-tocol in the posterior maxilla and mandible through

analysis of implant survival at 1 year. Eighty two ITIsandblasted, acid-etched (SLA) implants in 40 pa-tients were loaded between 0 and 11 days after im-plant placement. The restorations consisted of either2 splinted crowns or a 3-unit fixed prosthesis. Allrestorations were put into full functional occlusion.Periapical radiographs were evaluated for changes increstal bone level from baseline to 1 year postloading.Three patients implants were not loaded because oflack of primary stability, and a fourth patient was ex-cluded from the study because of a protocol violation(more than 4 implants were used).The mean bone lossat 1 year 0.52 0.98. The early results from this studyindicate that early and immediate loading of two im-plants in the posterior maxilla and mandible may besuitable in selected patients. On the basis of one yearobservation, the results appear similar to thoseachieved with a delayed procedure.17

Mohamed S Erakat, Sung-Kiang Chuang MeghanWeed, Thomas B. Dodson estimated the 1-year sur-vival rate of immediate vertical load splinted lockingtaper implants and identified the risk factors for im-plant failure. The study cohort was composed of 209patients who received 477 implants. The overall oneyear Kaplan Mayer survival estimate was 90.3 %. Af-ter controlling other variables, 3 variables-timing ofimplant placement relative to extraction (delayed im-plant placement after tooth extraction), coating ofimplant (uncoated), and increased number of pon-ticswere associated with an increased risk for im-plant failure. An overall 1-year survival estimate of90.3 % (95 % CL: 86.9 %, 93.7 %) was calculated forimmediately loaded splinted implants. After control-ling other variables, 3 variables-timing of implantplacement relative to extraction (delayed implantplacement after tooth extraction), coating of implant(uncoated), and increased number of ponticswereassociated with an increased risk for implant failure.18

Roberto Cornelini, Filippo Cangini, Ugo Covani,Antonio Barone, Daniel Buser evaluated the succesrate at 12 months of titanium dental implants placedin the posterior mandible and immediately loadedwith 3-unit fixed partial dentures. Patients withmissing mandibular premolars and molars wereenrolled in this study. Forty implants with a sand-blasted, large grit, acid-etched (SLA) surface (Strau-mann) were placed in 20 patients. Implant stabilitywas measured with resonance frequency analysisusing the Osstell device. Implants were included inthe study when the stability quotient (ISQ) exceeded62. At 12 months, only one implant had been lost be-cause of an acute infection. The remaining 39 im-plants were successful, resulting in a 1-year successrate of 97.5 %. Neither peri-implant bone levels,measured radiographically, nor implant stabilitychanged significantly from baseline to the 12 monthfollow-up.

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6!2)/323#2%72%4!).%$#/-0/.%.43&/2-/2%0/33)"),)4)%3

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Tab. 2_Summarized data from thestudies /approaches used in this

review with reference to earlyloading.

Tab. 3_Summarized data from thestudies/approaches used in this

review with reference to delayed loading.

implants3_2010

The findings from this clinical study showed thatthe placement of SLA transmucosal implants in themandibular area and their immediate loading with 3-unit fixed partial dentures may be a safe and successful procedure.19 Gioacchino Cannizzaro,Michele Leone, Marco Esposito have performed a oneyear follow-up of a single cohort study. Thirty threeconsecutively treated edentulous patients received202 implants in the maxila. In 10 patients, 53 implantswere immediately inserted in fresh extraction sockets.Three implants in two patients did not reach sufficientstability and were left to heal for 45 to 90 days. Allrestorations (21 fixed prostheses and 12 overden-tures) were delivered the same day of the surgery. Nomajor complication occurred. Five patients experi-enced biologic complication, e.g. peri-implantitis; tenexperienced prosthetic complication. Two implantsfailed in two patients but were successfully replacedthe same day they were removed. No prosthesisfailed. Implants placed in the edentulous maxilla witha flapless procedure can be successfully loaded thesame day of surgery.20 The activity around dental im-plants has been approached by Hiroto Sasaki et al.who performed a study to determine dynamicchanges in bone metabolism around osseointegrated

titanium implants under mechanical stress. After in-sertion of implants, the uptake ratio increased duringthe first week and then decreased gradually. It wassignificantly higher than baseline on days 4.7 and 10(p < 0.01 Friedman test) and during the second andthird week (p < 0.5 Steel test). However, it was not sig-nificantly higher at 4 weeks and 7 weeks (i.e. meta-bolic activity had returned to the baseline level). Theuptake ratio changed with the loading. With 2.0 and4.0-N loading, change of activities over the 7 weekexperimental period was almost the same in termsof magnitude and timing.The ratio reached a maxi-mum during the first week (more than twice thatwithout loading) and then decreased a little. Meta-bolic activity returned to the baseline level at about2 to 7 weeks after loading. The ratio from 3 days to6 weeks after loading was significantly higher thanwithout loading (Friedman and Steel test, P < 0.05).There was no significant difference 7 weeks afterloading. The results for the 0.5 and 1.0-N loadinggroups were similar but different from those for the2.0 and 4.0-N loading groups. With the smallerloadings, the uptake ratio gradually increased afterloading and returned to the baseline level at 7 days.It then decreased, reaching baseline level at 2 to 7


Sit. Impl.type

Followup

No.of pac. No.of impl.

Succ.rate


Earlyloading

2Months

Ed. max.Ed. mandib.

Osseotite 60 Months 142 pac.526 impl.

97.9 % Sullivan et al. B

Earlyloading

1-11Days

Ed. post.mandib.Ed. post.max.

ITIStraumann


98.8 % GiuseppeLuongo et al.

B

Earlyloading

7 Days Ed.mandib.

NovumBrnemark


90 % Els De Smetet al.

B


Sit. Impl.type

Followup

No.of pac. no.ofimpl.

Succ.rate


Delayedloading

4Months

Ed.mandib.

NovumBrnemark

1 YearHalf 2 Years

10 pac.20 impl.

90 % Els De Smetet al.

C

Delayedloading

3Months

Max. estheticzone

Sweden &Martina


100 % RobertoCrespi et al.

B

Delayedloading

4Months

Part.Edent.

ZimmerSwiss Plus



B

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implants3_2010

weeks after loading. With 1.0-N loading, the uptakeratio did not differ among measurement points(Friedman and Steel tests, P > .05 ). The uptake ratioswith the 2.0 and 4.0 loads were significantly higherthan those with the 0.5 and 1.0-N loads (Tukey test,P < 0,5).21

_Discussion

Successfully osseointegrated dental implants areanchored directly to the bone. However, in the pres-ence of movement , a soft tissue interface may incap-sulate the implant causing its failure.To minimize therisk of soft tissue encapsulation, it has been recom-mended that implants should be kept load-free bysubmerging them during the healing period.24

Immediatly loaded or early loaded implants afterinsertion develop special and specific clinical implica-tions with an impact on the treatment time. If it canshortened to a very large extent it involves a signifi-cant fact to the benefit of the patients. The main pur-pose of these studies is actually the achievement of asuccessful final prothesis. Implant loss is a significantrisk factor in this respect.

This review has been intended for gathering dataand information available in reference literature inorder to achieve a clinical conclusion as to fixed or re-movable implant-supported prostheses based ontime of loading. Attempts to use standard systematicreview procedures (application of scientific strategiesin ways that limit bias to the assembly, critical ap-praisal and synthesis of all relevant studies that ad-dress a specific clinical question) have not been en-tirely possible because of report variability, and thislimits the ability to draw conclusive comments fromthe work.

Nowadays, immediate or early dental implantsloading with a careful patients selection is possible.The clinicians experience is an obligatory prerequisitein reaching optimum results with immediate loading.One of the conditions or requirements influencing theprocedure success appears to be the high primary sta-bility of the implant at the insertion time. In future,additional and well structured studies are importantand necessary to complete a clear protocol for imme-diate and early loading. No statistic difference forprothesis and implants success rate or marginal boneloss with different time of implant loading has beenobserved. All known risk factors and contraindica-tions for osseointegration with a standard protocolwill be equally or even more important with immedi-ate or early loading protocols. It is thus implied thatsuccessful osseointegration with reduced loadingprotocols requires critical case selection and meticu-lous surgical and prosthetic management.

A surgical technique that minimizes heat genera-tion and pressure necrosis is of particular importancewith both early and immediate implant loading. It isalso dependent on the quality and quantity of exist-ing bone at the implant site and the ability to achieveand maintain adequate stability of the implant so thatmicromotion is kept below the biological threshold.The level of skill and experience of the surgeon play arole in treatment outcomes. The presence of infectionin the implant area will affect osseointegration. Un-treated periodontitis and periapical pathology mustbe addressed before implant placement, independentof the loading protocol.

Management of micromotion of the implant iscritical for osseointegration and many studies stressthe importance of minimizing functional loading inboth centric and lateral excursion. Non axial loadingis difficult to measure clinically and the ideal occlusalscheme has not been outlined. It is therefore impos-sible to state that parafunction is an implicit contra-indication to immediate or early loading but it is gen-erally considered to be a risk factor.

Relatively few data about the relationship be-tween soft tissue and immediate or early loading areavailable. Marginal recessions around the immedi-ately loaded implant were comparable to those con-ventionally loaded.22, 23

Smoking has been shown to have a negative im-pact on osseointegration 25, 26 and, as such, it must bealso considered a potential risk factor for immediateand early loading protocols even though some stud-ies showed that immediate loading of oral implantsmay be successful in heavy smokers under some cir-cumstances.10, 27, 28

It is fundamentally necessary for a treatment planto offer an advantage to the patient. Immediate andearly loading benefits reduce surgical steps by elimi-nating the second procedure, shorten treatment timeand provide a functional and psychologic advantageof prosthetic rehabilitation.

Immediate restauration or loading may be partic-ulary attractive to a patient as temporization with aremovable appliance is not required after implant fix-ture placement. The advantage must be carefully con-sidered against a potential increased risk of failure forimmediate or early loading times.

An increased success rate was generally stated inthe studies; however, two studies 15, 18 have revealed arelatively high failure rate. In one study15, one patientof each group lost both implants. The loss occurred sixmonths after loading in delayed group and one monthafter loading in early group. In the immediate group,

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one patient lost both distal implants five months af-ter loading. In two other patients, distal implantsfailed after one year of loading. Marginal bone losswas the highest for the immediate group. In anotherstudy18, there has been reported a success rate of 90.3 %, i.e. 47 lost implants out of 477 inserted im-plants, respectively. It might be important to specifythat Bicon implants were used in the study. It is worthmentioning that, in general, the success rate was high(95.6 % 100 %), a fact confirming immediate andearly loading of dental implants to be a viable treat-ment option.7,8,9,10,11,12,13,14,16,17,19,20 Marginal bone losswas observed to be higher with immediately loadedimplants.15 Furtheron, bone loss has not been ex-tended beyond the first implant thread.13,16 Both im-plant length reducing and diameter shortening in-crease the risk of failure.9 Another important aspectis that immediate loading can be achieved under cir-cumstances of a high primary stability.8,9,10,11,12,13,14,15,16,17,18,19,20

_Conclusion and Clinical Relevance

Nowadays, immediate and early loading with out-comes comparable to conventional results is possible.However, a rigurously and thoroughly selected surgi-cal and prothetic management is of utmost impor-tance and necessity in achieving the goal. It is alsocompulsory for dental implants to show a very goodprimary stability and bone quantitaty and quality aswell as bruxism and parafunctional habits must becorrectly assessed. The risk of failure with immediateand early loading is extremely high in the lateral max-illary area due to poor bone quality as well as whenone tooth only is replaced. A high success rate hasbeen observed when optimum density bone existsand when the implants are splinted. Biological limitsin the immediate and early loading process of dentalimplants have not been entirely defined yet. Furtherresearches are required and important for a more ac-curate setting of limits between immediate, early anddelayed loading of dental implants.

_Summary

The scope of this review is to find an answer to thequestions when and how implants can be loadedin different time after insertion. For the purpose ofthis review, immediate loading was defined as an im-plant put in function within 48 hours after its place-ment; early loading as those implants put in functionfrom 48 hours up to 3 months after insertion, andconventional loading as those implants put in func-tion between 3 to 6 months after placement. The re-view has been accomplished on the basis of 14 stud-ies selected out of 26, with a minimum 12 month fol-low up. The concern for immediate or early loading af-ter insertion determines special and specific clinical

implications with an impact on the treatment timesince it is shortened to a very large extent, being thusa benefit to the patients.

The main purpose of the studies underlying this re-view is in fact the success of the final prothesis, sinceimplants loss engenders a great risk for protheses. Im-mediate or early loading of dental implants is nowa-days possible for carefully selected patients. Allknown risk factors and contraindications for osseoin-tegration with a standard protocol will be equally oreven more important with immediate or early loadingprotocols. It is thus implied that successful osseoin-tegration with reduced loading protocols requirescritical case selection and meticulous surgical andprosthetic management. A surgical technique thatminimizes heat generation and pressure necrosis is ofparticular importance with both early and immediateimplant loading. It is also dependent on the qualityand quantity of existing bone at the implant site andthe ability to achieve and maintain adequate stabilityof the implant so that micromotion is kept below thebiological threshold. The level of skill and experienceof the surgeon play a role in treatment outcomes. Bi-ological limits in the immediate and early loadingprocess of dental implants have not been entirely de-fined yet. Further researches are required and impor-tant for a more accurate setting of limits between im-mediate, early and delayed loading of dental implants.

For reviewing this article and the support I thank Dr Roland Hille, Dr Rolf Vollmer and Dr Mazen Tamimi.

Cited literature upon request.

Dr Marius Hary Silvasanstr. Romulus nr. 34A300238 Timisoara, RomaniaPhone: +40 722 367 490Fax: +40 256 294 085

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Timing of Dental Implant Loading-Hary Silvasan

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