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Literature Update Jun - Aug 2010

Clinical Oral Implants Research

Vol. 21 No. 7 (July 2010) Vol. 21 No. 8 (August 2010)

Degidi M, Nardi D, Piattelli A.  A comparison between immediate loading and immediate restoration in cases

of  partial  posterior  mandibular  edentulism:  a  3.year  randomized  clinical  trial.  Clin  Oral  Implants  Res

2010;21(7):682-687.

Either immediate loading or immediate restoration was performed in 50 patients with partial posterior mandibular edentulism (25 patients per group). A total of 100 implants were placed in healed sites. The prostheses in the restoration group were placed out of occlusal contact, and both groups received definitive restorations in occlusion after 6 months. Marginal bone loss was evaluated after 6, 12, 24 and 36 months. Mobility was detected in two implants, one in each group. Mean marginal bone loss after 3 years was 0.987

± 0.375 mm and 0.947 ± 0.323 mm in the immediate restoration and immediate loading groups, respectively; there was no significant difference between the groups. Immediate rehabilitation was therefore predictable with both procedures.

 

Mardas N, Chadha V, Donos N.  Alveolar ridge preservation with guided bone regeneration and a synthetic bone substitute or a bovine-derived xenograft: a randomized, controlled, clinical trial. Clin Oral Implants Res 2010;21(7):688-698.

Following single tooth extraction in 27 patients, sockets were grafted with either Straumann BoneCeramic

(SBC; test) or Bio-Oss (control), both covered with a collagen barrier membrane; complete soft tissue coverage was not achieved. The residual ridge was evaluated and biopsies were taken after 8 months. Reduction of the bucco-lingual alveolar ridge dimensions was significantly less in the test group (1.1 ± 1 mm versus 2.1 ± 1 mm), while mesio-distal bone height was equally preserved in both groups. No differences in buccal and palatal bone width were observed between the groups. Histology showed new bone formation in the apical part of the biopsies, while dense fibrous connective tissue was observed in the coronal part.

 

Chang M, Wennström JL.  Bone alterations at implant-supported FDPs in relation to inter-unit distances: a 5- year radiographic study. Clin Oral Implants Res 2010;21(7):735-740.

A total of 43 patients with 48 fixed prostheses supported by 130 implants were enrolled in a supportive care

program, with radiography performed at prosthesis placement and after 1 and 5 years. Mean bone loss after

5 years was 0.1 mm, 0.4 mm and 0.2 mm at the tooth, implant and mid-proximal bone crest, respectively, and mean mid-longitudinal bone loss at implant/implant units was 0.5 mm at the implants and 0.3 mm mid- proximally. Change in BIC was found to be a significant predictor for 5-year mid-proximal bone level change at implant/implant units, but no significant associations were observed at tooth/implant units.

 

Passeri G, Cacchioli A, Ravanetti F, Galli C, Elezi E, Macaluso GM.  Adhesion pattern and growth of primary human osteoblastic cells on five commercially available titanium implant surfaces. Clin Oral Implants Res

2010;21(7):756-765.

Human primary osteoblastic cells were cultured on five titanium surfaces: polished; machined; sandblasted/acid-etched; sandblasted/acid-etched and modified with H2O2 rinse; and, titanium plasma- sprayed. Cell growth was measured after 3, 7 and 9 days and the production of osteocalcin and osteoprotegerin was evaluated. Cell shape and anchorage was affected by surface topography, with large lamellipodia observed on the polished and machined surfaces and thin filopodia on both sandblasted/acid- etched surfaces. Cell proliferation was greater on the rough surfaces and focal adhesions were stronger on both sandblasted/acid-etched surfaces. Osteoprotegerin increased on all surfaces over time, but osteocalcin production was highest on the sandblastzed/acid-etched/H2O2 rinse surface.

 

Simonis P, Dufour T, Tenebaum H.  Long-term implant survival and success: a 10-16-year follow-up of non- submerged dental implants. Clin Oral Implants Res 2010;21(7):772-777.n

A total of 55 patients (from an original 76) who received 131 implants between 1990 and 1997 were available

for a 10-16-year clinical and radiographic examination and a questionnaire on satisfaction. Cumulative implant survival up to 16 years was 82.94%, and the biological and technical complication rates were 16.94% and 31.09%, respectively. Most implant losses and biological complications were concentrated in a relatively small number of patients. Patients with a history of periodontitis were noted to have lower implant survival and were more prone to biological complications.


Implants Res 2010;21(8):789-793.

Subjects attending a dental hospital were presented with two hypothetical clinical scenarios, i.e. missing one anterior or posterior tooth. Clinical procedures, outcomes and potential complications of various treatment options were then explained, as well as the consequences of no treatment. The subjects were then asked to bid how much they would be prepared to pay for tooth replacement, with a starting bid of HK $20,000, decreasing in HK $1000 increments until the subject chose the opposite option or the bid reached HK $0. Implant treatment for the replacement of anterior or posterior teeth was chosen by 94% and 84% of subjects. And the mean willingness-to-pay amounts were HK $11,000 and HK $10,000, respectively. Female subjects, those with no missing teeth or restorative need, and those with higher levels of education were willing to pay greater amounts, and these were considered independent predictors.

 

Tran BLT, Chen ST, Caiafa A, Davies HMS, Darby IB.  Transmucosal healing around peri-implant defects:

crestal and subcrestal placement in dogs. Clin Oral Implants Res 2010;21(8):794-803.

In the mandibular premolar regions of three dogs, 23 implants were placed 3 months after tooth removal. Five were control implants, placed at crestal bone level, and 18 were test implants placed with surgically created peri-implant defects at either the crestal bone level (nine implants) or 2 mm below the crestal bone level (nine implants). After 3 months of healing, greater BIC was observed in the coronal region for all implants, but the healing response was incomplete for the test implants after 1 month, compared to the control implants. Histometric measurements for the test implants were more coronal or closer to the implant margin compared to the control implants, and the degree of osseointegration was similar for both test implant groups.

 

Payer M, Heschl A, Wimmer G, Wegscheider W, Kirmeier R, Lorenzoni M.  Immediate provisional restoration of screw-type implants in the posterior mandible: results after 5 years of clinical function. Clin Oral Implants Res 2010;21(8):815-821.

A total of 40 implants were placed in 24 patients to replace mandibular molars and premolars, and were

immediately provisionalized after placement. Bone levels and implant survival/success were assessed after

12, 24, 36, 48 and 60 months. Significant bone loss was observed in the first year after final restoration, but no further significant increase occurred between 12 and 60 months. Two implants were lost, giving an implant survival rate of 95%; the corresponding implant success rate was 92.5% (two failures plus one implant with excessive bone loss). Careful patient selection appeared to be a key criterion for success.

 

Koizumi H, Sur J, Seki K, Nakajima K, Sano T, Okano T. Effects of dose reduction on multi-detector computed tomographic images in evaluating the maxilla and mandible for pre-implant surgical planning: a cadaveric study. Clin Oral Implants Res 2010;21(8):830-834.

Micro-detector CT with variable tube currents of 80, 40, 20 and 10 mA was used to evaluate the maxillae and mandibles  in  six  cadaver  specimens.  Multi-planar  images  were  created  and  assessed  by  five  oral radiologists for visibility of various anatomical landmarks, and the quality of the images was compared to the

80 mA images. The results indicated that anatomical landmarks could be visualized on 40 mA images to almost the same quality as 80 mA images, and 20 mA images were acceptable for diagnostic purposes, but with substantial deterioration of image quality. Significant dose reduction is therefore possible for pre-surgical implant planning with CT.

 

Widmann  G,  Zangeri  A,  Keiler  M,  Stoffner  R,  Bale  R,  Puelacher  W.  Flapless  implant  surgery  in  the edentulous  jaw  based  on  three  fixed  intraoral  reference  points  and  image-guided  surgical  templates: accuracy in human cadavers. Clin Oral Implants Res 2010;21(8):835-841.

Implant planning was performed on the basis of CT scans of edentulous cadaver specimens. Surgical templates were fabricated, and the registration mouthpiece and surgical template were supported via three fixed reference points. Implants were inserted through the guide sleeves and the accuracy was evaluated via post-surgical CT. A total of 51 implants were placed in five maxillary and three mandibular edentulous specimens. Mean SE) total and lateral error was 1.1 ± 0.6 mm and 0.7 ± 0.5 mm, respectively, at the implant base, and 1.2 ± 0.7 mm and 0.9 ± 0.7 mm at the implant tip and the mean angular error was 2.8° ±

2.2°. Similar accuracy to tooth-supported surgical templates or surgical navigation was therefore found.


 

von See C, Gellrich N-C, Jachmann U, Laschke MW, Bormann K-H, Rücker M. Bone augmentation after soft-tissue expansion using hydrogel expanders: effects on microcirculation and osseointegration. Clin Oral Implants Res 2010;21(8):842-847.

Bone grafts from eight isogenic rats and were implanted in eight rats without tissue expansion and eight rats

after tissue expansion. Hydrogel expanders were inserted subperiostally in the tissue expansion group at the augmentation sites. Microcirculation was monitored for 19 days and histological samples were evaluated. Microvessel density was significantly higher in the region above the augmentation material in the tissue expansion group over the whole study, but physiological microcirculation was observed in both groups. Osseointegration of the graft was observed in the tissue expansion group, while connective and granulation tissue was observed in the group without tissue expansion. Hydrogel expanders may therefore increase the probability of success in bone augmentation.

 

Northdurft F, Pospiech P.  Prefabricated zirconium dioxide implant abutments for single-tooth replacement in the posterior region: evaluation of peri-implant tissues and superstructures 12 months after function. Clin Oral Implants Res 2010;21(8):857-865.

A total of 24 patients received 40 implants, which were subsequently restored with all-ceramic Y-TZP

abutments and all-ceramic crowns. Clinical parameters and mesial and distal bone levels were evaluated after 12 months, and implant stability was measured. Sulcus fluid flow rate and modified sulcus bleeding index indicated stable and healthy soft tissues, and probing pocket depth was generally low. Proximal bone defects were reduced from -1.1 mm to -1 mm. No implant or crown losses were recorded, but chipping of the veneering ceramic was observed in four cases. No mechanical failure of the all-ceramic abutments therefore occurred.

 

Klinger A, Asad R, Shapira L, Zubery Y.  In vivo degradation of collagen membranes exposed to the oral cavity. Clin Oral Implants Res 2010;21(8):873-876.

Collagen membranes of three different types (ribose cross-linked, glutaraldehyde cross-linked or non-cross-

linked) were placed over the buccal mucosa in the premolar and molar region in 20 subjects. A periodontal dressing was placed over the membrane, which was removed after 10 days to assess membrane integrity. Discomfort, pain or dislodging of the pack led eight subjects to withdraw from the study. Marked differences in membrane integrity between the three types were observed. The results indicated that the ribose cross- linked membrane appeared to be more resistant to degradation.

 

European Journal of Oral implantology

Vol. 3 No. 2 (June 2010)

Esposito M, Grusovin MG, Loli V, Coulthard P, Worthington HV. Does antibiotic prophylaxis at implant

placement  decrease  early  implant  failures?  A  Cochrane  systematic  review.  Eur  J  Oral  Implantol

2010,3(2):101-110.

The authors performed a literature search for randomized controlled trials comparing the outcomes of prophylactic regimens versus no antibiotics in implant placement. Four trials were identified; three compared

2 g amoxicillin preoperatively versus placebo (927 patients) and one compared 1 g amoxicillin preoperatively plus 500 mg four times daily versus no antibiotics (80 patients). Significantly more patients experienced implant failures in the groups not receiving antibiotics, but other outcomes were not statistically significantly different. Some evidence therefore suggests that prophylactic amoxicillin may reduce implant failures in ordinary conditions.

 

Cannizarro G, Torchio C, Felice P, Leone M, Esposito M.  Immediate occlusal versus non-occlusal loading of single  zirconia  implants.  A  muticentre  pragmatic  randomised  clinical  trial.  Eur  J  Oral  Implantol

2010,3(2):111-120.

A total of 40 edentulous patients each received a single zirconia implant loaded immediately either occlusally or non-occlusally. There were five early implant failures (three occlusally loaded and two non-occlusally loaded) and three complications were noted. Peri-implant bone was gradually lost in both groups up to 1 year (0.9 mm and 0.7 mm in the occlusal and non-occlusal loading groups, respectively). An association was also noted between immediate post-extraction implants and implant failures.


 

Alissa R, Esposito M, Horner K, Oliver R.  The influence of platelet-rich plasma on the healing of extraction sockets. An explorative randomised clinical trial. Eur J Oral Implantol 2010,3(2):121-134.

A total of 15 extraction sockets were treated with PRP in 12 patients and 14 control sockets were left

untreated in 11 patients. Pain was significantly greater in the control group for the first 3 days, and analgesic consumption was significantly higher for the first and second days. There were significant differences in favor of PRP treatment for presence of bad taste/bad smell in the mouth and food stagnation in the operation area. Two dry sockets and one inflamed alveolus occurred in the control group, and soft tissue was significantly better in the PRP group. Significant differences favoring PRP were also detected radiographically for sockets with dense homogeneous trabecular pattern and trabecular pattern for bone volume, but there were no differences for trabecular separation, length, width of number. PRP may therefore have some benefits, but data are currently insufficient.

 

Esposito M, Cannizarro G, Bozzoli P, Checchi L, Ferri V, Landriani S, Leone M, Todisco M, Torchio C, Testori T, Galli F, Felice P.  Effectiveness of prophylactic antibiotics at placement of dental implants: a pragmatic multicentre placebo-controlled randomised clinical trial. Eur J Oral Implantol 2010,3(2):135-143. Patients  scheduled  for  implant  surgery  were  randomized to received 2 g amoxicillin (252 patients) or identical placebo (254 patients) 1 h prior to implant placement and were evaluated 1 and 2 weeks and 4 months later. There were four prosthesis and seven implant failures in the antibiotic group compared to 10 prosthesis and 13 implant failures in the placebo group. The number of complications was similar (11 in the antibiotic group, 13 in the placebo group). Differences were not significant but the risk of implant failure was increased without antibiotic prophylaxis.

 

Cairo F, Nieri M, Gori AM, Tonelli P, Branchi R, Castellani S, Abbate R, Pini-Prato GP.  Markers of systemic inflammation in periodontal patients: chronic versus aggressive periodontitis. An explorative cross-sectional study. Eur J Oral Implantol 2010,3(2):147-153.

Blood samples from 45 systemically healthy patients with either chronic (21 patients) or aggressive (24 patients) periodontitis were evaluated for high-sensitivity CRP, cytokine and chemokine levels. No significant differences were found between the groups for periodontal parameters or inflammatory markers, indicating a similar inflammatory profile for chronic and aggressive periodontitis.

 

Puig CP.  A retrospective study of edentulous patients rehabilitated according to the ‘all-on-four’ od the ‘all- on-six’ immediate function concept using flapless computer-guided implant surgery. Eur J Oral Implantol

2010,3(2):155-163.

A total of 195 implants were placed and immediately loaded in 30 patients to support 25 maxillary (128 implants) and 17 mandibular (67 implants) full-arch prostheses via the ‘all-on-four’ or ‘all-on-six’ protocols; provisional prostheses were placed immediately with definitive prostheses after 6-12 months. Implant positioning and guided flapless implant placement was by means of Procera software. There were four implant failures in three patients (two each in the maxilla and mandible), three of which were successfully replaced. No definitive prostheses failed and no patients dropped out of the study, but three patients were surgically and antibiotically treated for apically infected implants. Both surgical protocols appeared to be viable and predictable, but may be sensitive to the clinician’s experience.

 

European Journal of Oral Sciences

Vol. 118 No. 4 (August 2010)

Taylor B, Tofler G, Morel-Kopp M-C, Carey H, Carter T, Elliott M, Dailey C, Villata L, Ward C, Woodward M, Schenck  K.   The  effect  of  initial  treatment  of  periodontitis  on  systemic  markers  of  inflammation  and

cardiovascular risk: a randomized controlled trial. Eur J Oral Sci 2010;118(4):350-356.

A total of 136 patients with chronic periodontitis were randomized to receive initial periodontal treatment (test) or no treatment (control) in a 3-month study. Cardiovascular risk factors and hematological, inflammatory and metabolic markers were measured at the start and end of the study. Data were available for 51 test and 64 control patients, and the results showed a non-significant trend towards lower fibrinogen levels in the test group and a significant increase in hemoglobin and hematocrit after intervention. Systemic effects of periodontal treatment were therefore observed.


 

Meijndert L, van der Reijden WA, Raghoebar GM, Meijer HJA, Vissink A.  Microbiota around teeth and dental implants  in  periodontally  healthy,  partially  edentulous  patients:  is  pre-implant  microbiological  testing relevant?

Eur J Oral Sci 2010;118(4):357-363.

Subgingival microbial samples from 93 patients requiring single tooth replacement were obtained before implant treatment and after 1 year. Threshold levels for periodontal breakdown were applied, and periodontal treatment was given to patients with levels of pathogens above these thresholds. One or more marker pathogens were found in 49.5% of subjects at baseline, and periodontal treatment reduced the levels to below the thresholds in 78.3% of these patients. Marker pathogens were above the threshold level in 74.1% of patients after 1 year. The long-term effectiveness of reducing pathogen levels prior to implant treatment was therefore limited; pre-implant reduction did not predict post-implant levels. Pre-implant microbiological testing may therefore not be relevant.

 

Implant Dentistry

Vol. 19 No. 3 (June 2010)

Sánchez-Ayala A, Lagravère MO, Gonçalves TMSV, Lucena SC, Barbosa CMR. Nutritional effects of implant

therapy in edentulous patients – a systematic review. Implant Dent 2010;19(3):196-207.

Studies relating to the nutrient intake improvement of edentulous subjects rehabilitated with various treatments were reviewed. Despite an extensive literature search, only five articles met the selection criteria. Inadequate nutrient intake after treatment was found in two of these, while a randomized controlled trial showed an improvement in nutrient intake after treatment and another found adequate nutritional intake both before and after treatment. No difference between conventional and implant treatment was found in these four studies, but the fifth study indicated a higher risk of malnutrition for those wearing conventional complete dentures.

 

Chow   YC,   Wang   H-L.    Factors   and   techniques   influencing   peri-implant   papillae.   Implant   Dent

2010;19(3):208-219.

A literature search was performed for articles relating to esthetics in terms of inter-implant papillae. Factors that  can  influence  the  appearance  of  inter-implant  papillae  include  crestal  bone  height,  interproximal distance, gingival width and the width of keratinized tissue. Promotion of inter-implant papillae formation has also been successfully achieved using a number of techniques.

 

Acocella A, Bertolai R, Sacco R. Modified insertion technique for immediate implant placement into fresh extraction socket in the first maxillary molar sites: a 3-year prospective study. Implant Dent 2010;19(3):220-

228.

Each of 68 patients scheduled for extraction of a first maxillary molar immediately received an implant in the fresh extraction socket. Regenerative therapy was simultaneously performed, if necessary. Single crowns were placed after 3 months. After 3 years, there were three implant failures, giving a cumulative survival rate of 97.96%. Immediate implant placement in the maxillary first molar position, with appropriate regenerative material, is therefore a valid treatment option.

 

Bilhan H, Mumcu E, Erol S, Kutay Ö.  Influence of platform-switching on marginal bone levels for implants with mandibular overdentures: a retrospective clinical study. Implant Dent 2010;19(3):250-258.

A total of 51 patients with 126 implants supporting mandibular overdentures appeared for routine recall visits

after 6, 12, 24 and 36 months and were included in the study group. Mean marginal bone level change was assessed from successive radiographs. Significantly lower bone loss was observed for platform-switched implants after 36 months, although rates of mesial and distal bone loss differed at 6, 12 and 24 months.

 

International Journal of Oral and Maxillofacial Implants

Vol. 25 No. 3 (May/June 2010)

Baixe S, Fauxpoint G, Arntz Y, Etienne O.  Microgap between zirconia abutments and titanium implants. Int J Oral Maxillofac Implants 2010;25(3):455-460.

For each of four different systems (Procera zirconia, Cercon Balance Anterior, ZirDesign and Straumann

Cares ceramic) assemblies (five per system) were embedded in epoxy, cut along the long axes, polished and examined by scanning electron microscopy for microgaps. Mean marginal microgap was 0.89 ± 1.67 μm, and significant differences were observed between the systems (Cercon 0.38 ± 0.28 μm, ZirDesign 0.55

± 0.23 μm, Procera 1.83 ± 3.21 μm, Straumann Cares 0.90 ± 0.59 μm). The microgap quickly decreased from the outer region to the inner in all systems. The mean microgap for flat connection systems was greater than that for internal conical connection systems.


 

Hudieb M, Wakabayashi N, Suzuki T, Kasugai S. Morphologic classification and stress analysis of the mandibular  bone  in  the  premolar  region  for  implant  placement.  Int  J  Oral  Maxillofac  Implants

2010;25(3):482-490.

Scans of the premolar region were performed for 102 patients with missing mandibular premolars and were classified into nine groups according to bone morphology and alveolar crest. Finite element models were then constructed, with implants and superstructures, and 200 N loads applied 30° buccal from the vertical axis. Maximum compressive stresses were observed in the lingual cervical regions, but no influence of bone morphology on stress distribution was observed, but maximum stress and strain was affected by the alveolar contour; microstrain over 4,000 was only seen when the alveolar crest was lingual in relation to the body of the mandible. The alveolar crest contour therefore plays a role in maintaining peri-implant bone levels.

 

Waasdorp J, Reynolds MA.  Allogeneic bone onlay grafts for alveolar ridge augmentation: a systematic review. Int J Oral Maxillofac Implants 2010;25(3):525-531.

A  literature  search  was  performed  for  clinical  studies  using  allogeneic  bone  grafts  for  alveolar  bone

augmentation. From an initial 35 publications identified, nine were included in the review (six case series, one prospective multicenter case series and two case reports). High graft incorporation and implant survival were found in observational studies, but most articles involved selected defects in the anterior region with < 3 years follow-up. Clinical evidence therefore differed in terms of defects, treatment and therapeutic endpoints. The potential for allogeneic block grafts was shown, but there is insufficient evidence to establish treatment efficacy.

 

Valderrama P, Jones AA, Wilson TG Jr, Higginbottom F, Schoolfield JD, Jung RE, Noujeim M, Cochran DL. Bone changes around early loaded chemically modified sandblasted and acid-etched surface implants with and without a machined collar: a radiographic and resonance frequency analysis in the canine mandible. Int J Oral Maxillofac Implants 2010;25(3):548-557.

A total of 72 implants, 36 with a 2.8 mm machined collar and 36 without a machined collar, were placed in six

dogs. Implant stability (by resonance frequency analysis) was measured weekly for 3 weeks, and the implants were loaded after 21 days. Periapical radiographs were taken at 3 weeks and 3, 6, 9 and 12 months. Implant stability increased by 5 ISQs for implants with a machined collar and by 7 ISQs for implants without a machined collar from implant placement to week 3. After 12 months, a mean bone loss of 1.0 mm was observed for the machined collar implants, compared to mean bone gain of 0.11 mm for implants without a machined collar. Coronal bone apposition was attributed to the properties of the chemically modified implant surface.

 

Degidi M, Daprile G, Piattelli A.  Determination of primary stability: a comparison of the surgeon’s perception and objective measurements. Int J Oral Maxillofac Implants 2010;25(3):558-561.

A total of 514 implants were placed in 152 patients. The surgeon was asked to indicate the probable ISQ

value after placement for all implants and the probable insertion torque for 483 implants. The actual values were measured and classified into low, medium and high groups. Mean perceived and actual RFA values were 72.2 ± 9.8 and 73.5 ± 10.2, respectively, and the perceived and actual insertion torque values were

39.1 ± 20.1 Ncm and 39.9 ± 20.7 Ncm, respectively. Good primary stability was obtained but was generally underestimated, especially in the presence of low of medium ISQ and torque values. However, the accuracy of prediction is not enough to prevent mistakes, so more systematic use of objective measurements is encouraged.

 

van Kesteren CJ, Schoolfield J, West J, Oates T.  A prospective randomized clinical study of changes in soft tissue  position  following  immediate  and  delayed  implant  placement.  Int  J  Oral  Maxillofac  Implants

2010;25(3):562-570.

In 24 patients, implants were either placed immediately or ridge preservation was performed with implant placement 3 months later. Soft tissue, vertical and ridge width measurements were performed after 6 months. Minimal recession of mid-buccal tissue margins was found after 6 months, with no differences between the groups. There was a significant decrease in interproximal soft tissue height, with no significant differences between the groups, but ridge width reduction was greater at the immediate implant sites. No significant relationship could be seen between tissue biotype and tissue changes. No differences in soft tissue changes were therefore noted between immediate and delayed implants.



Fickl S, Zuhr O, Stein JM, Hürzeler MB. Peri-implant bone level around implants with platform-switched abutments. Int J Oral Maxillofac Implants 2010;25(3):577-581.

A total of 89 implants were placed in 36 patients in two different groups: 75 wide diameter implants placed

subcrestally with regular diameter cover screws (platform-switched) or 14 regular diameter implants placed at crestal level with regular diameter cover screws. Radiographs were taken at prosthesis placement and after 1 year. Significantly less bone loss was observed at the platform-switched implants at both prosthesis placement and after 1 year, therefore suggesting that this configuration can limit crestal bone remodeling.

 

Weinländer M, Piehslinger E, Krennmair G.  Removable implant-prosthodontic anchorage of the edentulous mandible: five-year results of different prosthetic anchorage concepts. Int J Oral Maxillofac