Stability, marginal bone loss and survival of standard and modified sand-blasted, acid-etched implants in bilateral edentulous spaces: a prospective 15-month evaluation

Objectives: Chemical modification of the already proven sand‐blasted and acid‐etched (SLA) implant had increased its surface wettability and consequent early‐term osseointegration characteristics. The aim of this clinical trial was to compare the stability changes, success, survival, peri‐implant parameters and marginal bone loss (MBL) of the early‐loaded standard (SLA) and modified sand‐blasted, acid‐etched (modSLA) implants. Material and methods: A total of 96 SLA and modSLA implants were placed in a bi‐lateral, cross‐arch position to the jaws of 22 patients. Resonance frequency analysis (RFA) was used to measure the implant stability in the surgery and following healing after 1, 3 and 6 weeks. At the stage of loading, a panoramic X‐ray was obtained and RFA measurement was repeated for all implants. Implants were restored by metal–ceramic crowns and followed for 1 year to determine the success, survival rate, peri‐implant parameters and MBL. Results were compared by one‐ and two‐way ANOVA, log‐rank test and generalized linear mixed models (P<0.05). Results: One modSLA implant was lost after 3 weeks following the surgery yielding to a 100 and 97.91% success rate for SLA and modSLA implants, respectively (P=0.323). At the loading stage, modSLA implants showed significantly lower MBL (0.18 ± 0.05 mm) than SLA implants (0.22 ± 0.06 mm; P=0.002). In the loading stage, RFA value of the modSLA implants (60.42 ± 6.82) was significantly higher than the both implant types in the surgical stage (55.46 ± 8.29 and 56.68 ± 8.19), and following 1 (56.08 ± 7.01 and 55.60 ± 9.07) and 3 weeks of healing (55.94 ± 5.95 and 55.40 ± 6.50 for SLA and modSLA implants, respectively). Conclusions: modSLA implants demonstrated a better stability and a reduced MBL at the loading stage. Both SLA and modSLA implants demonstrated a favorable success and survival at the end of 15‐month follow‐up. To cite this article :
Karabuda ZC, Abdel‐Haq J. Arιsan V. Stability, marginal bone loss and survival of standard and modified sand‐blasted, acid‐etched implants in bilateral edentulous spaces: a prospective 15‐month evaluation.
Clin. Oral Impl. Res. 22 , 2011; 840–849
doi: 10.1111/j.1600‐0501.2010.02065.x     

Rehabilitation of irradiated patients with modified and conventional sandblasted acid-etched implants: preliminary results of a split-mouth study

Purpose: The aim of this study was to evaluate the success rate of chemically modified and conventional sandblasted acid‐etched surface (SLA) titanium implants in irradiated oral squamous cell carcinoma patients. Material and methods: Twenty patients with a mean age of 61.1 years were treated with dental implants after ablative surgery and radio‐chemotherapy of oral cancer. All patients were non‐smokers. The placement of SLA and modSLA implants was performed bilaterally according to a split‐mouth design. All 102 implants (50 SLA, 52 modSLA) placed showed an unloaded healing time of 6 weeks in the mandible and 10 weeks in the maxilla. Mean crestal bone changes using standardized orthopantomographies and clinical parameters like pocket depths, mPII and mBI were evaluated. Results: Of 102 implants, 55 implants (27 SLA implants, 28 modSLA) were located in the maxilla and 47 implants (23 SLA, 24 modSLA) in the mandible. The average observation period was 14.4 months. The amount of bone loss at the implant shoulder of SLA implants was 0.4 mm mesial and 0.4 mm distal. The modSLA implants displayed a bone loss of mesial 0.3 mm and distal 0.3 mm. Two SLA implants were lost resulting in a success rate of 96%. The success rate of modSLA implants was 100%. Conclusion: Regarding the data found in this investigation, we can conclude that implants with chemically modified and conventional SLA titanium surface show high success rates in irradiated patients. SLA implants with or without a chemically modified surface regardless of the location can be restored with a high predictability of success at least in the short time range observed. To cite this article:
Heberer S, Kilic S, Hossamo J, Raguse J‐D, Nelson K. Rehabilitation of irradiated patients with modified and conventional sandblasted, acid‐etched implants: preliminary results of a split‐mouth study.
Clin. Oral Impl. Res. 22 , 2011; 546–551
doi: 10.1111/j.1600‐0501.2010.02050.x     

Early loading of ITI implants supporting maxillary fixed full-arch prostheses

Objective: To evaluate the predictability of the early‐loaded sand‐blasted, large‐grit and acid‐etched (SLA) implants supporting maxillary‐fixed full‐arch prostheses. Material and methods: Ninety‐one ITI SLA implants were placed in 12 edentulous maxillae. The impressions were taken at 4 weeks post‐surgery. The abutments were tightened and the final fixed prostheses were cemented at 6 weeks after implant placement. Resonance frequency analysis (RFA) was conducted on the day of the surgery, at 4 and 6 weeks post‐surgery. Panoramic radiographs were taken immediately after surgery, at 4 weeks post‐surgery, immediately after prostheses attachment (baseline) and at the yearly follow‐ups. Results: The survival rate of implants was 98.90%. The success rate of prostheses was 100% during the follow‐ups. The radiographic result showed no radiolucency around the implants and the marginal bone level revealed no significant resorption compared with the baseline. The marginal bone level remained coronally beyond the first thread. The RFA results revealed Implant Stability Quotient (ISQ) values of 63.44±4.32, 57.14±4.25 and 66.43±3.78 for the three time points. Conclusions: The findings of this study indicated that early loading of ITI implants supporting maxillary fixed full‐arch prostheses should be predictable.     

Bone regeneration in dehiscence-type defects at non-submerged and submerged chemically modified (SLActive) and conventional SLA titanium implants: an immunohistochemical study in dogs

Objectives: The aim of the present study was to evaluate bone regeneration in dehiscence‐type defects at non‐submerged and submerged titanium implants with chemically modified (mod) and conventional sandblasted/acid‐etched (SLA) surfaces. Material and Methods: Standardized buccal dehiscence defects were surgically created following implant site preparation in both the upper and lower jaws of 12 beagle dogs. Both types of implants were randomly assigned to either a non‐submerged or a submerged healing procedure. After 1, 2, 4, and 8 weeks, dissected blocks were processed for histomorphometrical [e.g. new bone height (NBH), per cent linear fill (PLF), percentage of bone to implant contact (BIC‐D), area of new bone fill (BF)] and immunohistochemical analysis. Results: At 8 weeks, non‐submerged and submerged SLA implants revealed significantly lower mean NBH (1.1±0.8–1.9±1.2 mm), PLF (27.7±20.3–46.0±28.5%), BIC‐D (26.8±10.4–46.2±16.2%), and BF (1.3±0.9–3.4±2.8 mm²) values than respective modSLA implants [NBH (2.6±0.8–4.3±0.1 mm), PLF (64.2±19.4–107.2±4.7%), BIC‐D (67.5±18.8–82.1±14.8%), BF (2.9±1.0–6.7±1.1 mm²)]. Within modSLA groups, significantly highest BF values were observed at submerged implants. Conclusion: It was concluded that (i) modSLA titanium surfaces promoted bone regeneration in acute‐type buccal dehiscence defects and (ii) a submerged healing procedure improved the outcome of healing additionally.     

In vivo performance of zirconia and titanium implants: a histomorphometric study in mini pig maxillae

Objectives: To compare the bone tissue response to surface‐modified zirconia (ZrO₂) and titanium implants. Methods: Cylindrical low‐pressure injection moulded zirconia (ZrO₂) implants were produced with an acid‐etched surface. Titanium implants with identical shape, sandblasted and acid‐etched surface (SLA) served as controls. Eighteen adult miniature pigs received both implant types in the maxilla 6 months after extraction of the canines and incisors. The animals were euthanized after 4, 8 and 12 weeks and 16 zirconia and 18 titanium implants with the surrounding tissue were retrieved, embedded in methylmethacrylate and stained with Giemsa–Eosin. The stained sections were digitized and histomorphometrically analysed with regard to peri‐implant bone density (bone volume/total volume) and bone–implant contact (BIC) ratio. Statistical analysis was performed using Mann–Whitney' U‐test. Results: Histomorphometrical analysis showed direct osseous integration for both materials. ZrO₂ implants revealed mean peri‐implant bone density values of 60.4% (SD ± 9.9) at 4 weeks, 65.4% (SD ± 13.8) at 8 weeks, and 63.3% (SD ± 21.5) at 12 weeks after implantation, whereas Ti‐SLA implants demonstrated mean values of 61.1% (SD ± 6.2), 63.6% (SD ± 6.8) and 68.2% (SD ± 5.8) at corresponding time intervals. Concerning the BIC ratio, the mean values for ZrO₂ ranged between 67.1% (SD ± 21.1) and 70% (SD ± 14.5) and for Ti‐SLA between 64.7% (SD ± 9.4) and 83.7% (SD ± 10.3). For the two parameters investigated, no significant differences between both types of implants could be detected at any time point. Conclusion: The results indicate that there was no difference in osseointegration between ZrO₂ implants and Ti‐SLA controls regarding peri‐implant bone density and BIC ratio. To cite this article :
Gahlert M, Roehling S, Sprecher CM, Kniha H, Milz S, Bormann K. In vivo performance of zirconia and titanium implants: a histomorphometric study in mini pig maxillae.
Clin. Oral Impl. Res. 23 , 2012; 281–286.
doi: 10.1111/j.1600‐0501.2011.02157.x     

Effect of implant surface properties on peri-implant bone healing: a histological and histomorphometric study in dogs

Aim: The present study aimed to evaluate and compare two types of implants, i.e. grit‐blasted and acid‐etched implants (SLActive^®) with nano‐meter‐scale hydroxyapatite surface‐modified implants (NanoTite^?). Material and methods: For histological and histomorphometrical evaluation, 22 SLActive^® and 22 Nanotite^? implants were inserted in eleven Beagle dogs. The animals were divided into three groups of healing (A: 2 weeks; B: 4 weeks and C: 8 weeks). Two, 4 and 8 weeks after implantation, the animals were sacrificed and bone‐to‐implant contact (BIC %), first implant–bone contact (1st BIC) as well as amount of bone (BV) were assessed. Results: For SLActive^® and Nanotite^? implants, BIC% increased significantly over time. No statistically significant differences in BIC% were found between SLActive^® and Nanotite^? at all the respective implantation times. Moreover, for the different healing periods, no significant differences for BV between SLActive^® and Nanotite^? implants were found. Conclusions: The present study showed that SLActive^® and NanoTite^? implants induce a similar bone response after implantation for 2, 4 and 8 weeks in a non‐submerged position in the mandible of dogs. To cite this article:
Al‐Hamdan K, Al‐Moaber SH, Junker R, Jansen JA. Effect of implant surface properties on peri‐implant bone healing: a histological and histomorphometric study in dogs.
Clin. Oral Impl. Res. 22 , 2011; 399–405.     

Effect of immediate or delayed loading following immediate placement of implants with a modified surface

Objective: To evaluate the effect of the timing of loading on bone‐to‐implant contact (BIC) following immediate placement of implants with a hydrophilic sandblasted, large‐grit and acid‐etched surface (modSLA) into fresh extraction sockets in a minipig model. Material and methods: Six minipigs were used in this study. In each hemi‐mandible, two conical shape implants (TE, Straumann implants) with a hydrophilic surface (modSLA) were placed in fresh extraction sockets. In one side of the mandible (control), two implants were immediately placed in fresh extraction sockets. The implants were loaded after 4 weeks of healing. At the contralateral side (test), two implants were immediately placed and loaded. After 8 weeks of healing, the animals were sacrificed and histologically analysed. Results: During the experimental period, no implants were lost and all of them presented to be osseointegrated. The percentage of BIC was similar in both groups: 66.1% and 65.1% for the control and test group, respectively. Furthermore, the distance from the shoulder of the implant to bone crest and the distance from the shoulder to the first BIC were similar in both groups. Conclusion: Immediate implant placement and loading showed similar BIC with immediate placement and delayed loading when implants with a modSLA surface were used. Both procedures showed similar buccal bone crest levels, which presented some resorption irrespective of the treatment modality. To cite this article:
Liñares A, Mardas N, Dard M, Donos N. Effect of immediate or delayed loading following immediate placement of implants with a modified surface.
Clin. Oral Impl. Res. 22 , 2011; 38–46.
doi: 10.1111/j.1600‐0501.2010.01988.x     

Influence of topography and hydrophilicity on initial oral biofilm formation on microstructured titanium surfaces in vitro

Objectives: The aim of this study was to analyse the influence of the microtopography and hydrophilicity of titanium (Ti) substrates on initial oral biofilm formation. Materials and methods: Nine bacterial species belonging to the normal oral microbiota, including: Aggregatibacter actinomycetemcomitans, Actinomyces israelii, Campylobacter rectus, Eikenella corrodens, Fusobacterium nucleatum, Parvimonas micra, Porphyromonas gingivalis, Prevotella intermedia, and Streptococcus sanguinis were tested on Ti surfaces: pretreatment (PT [R_a<0.2 μm]), acid‐etched (A [R_a<0.8 μm]), A modified to be hydrophilic (modA), sand‐blasted/acid‐etched (SLA [R_a=4 μm]), and hydrophilic SLA (modSLA). Disks were incubated for 24 h in anaerobic conditions using a normal culture medium (CM) or human saliva (HS). The total counts of bacteria and the proportion of each bacterial species were analysed by checkerboard DNA–DNA hybridization. Results: Higher counts of bacteria were observed on all surfaces incubated with CM compared with the samples incubated with HS. PT, SLA, and modSLA exhibited higher numbers of attached bacteria in CM, whereas SLA and modSLA had a significant increase in bacterial adhesion in HS. The proportion of the species in the initial biofilms was also influenced by the surface properties and the media used: SLA and modSLA increased the proportion of species like A. actinomycetemcomitans and S. sanguinis in both media, while the adhesion of A. israelii and P. gingivalis on the same surfaces was affected in the presence of saliva. Conclusions: The initial biofilm formation and composition were affected by the microtopography and hydrophilicity of the surface and by the media used. To cite this article:
Almaguer‐Flores A, Olivares Navarrete R, Wieland M, Ximénez‐Fyvie LA, Schwartz Z, Boyan BD. Influence of topography and hydrophilicity on initial oral biofilm formation on microstructured titanium surfaces in vitro.
Clin. Oral Impl. Res. 23 , 2012; 301–307.
doi: 10.1111/j.1600‐0501.2011.02184.x     

Bone apposition around two different sandblasted, large-grit and acid-etched implant surfaces at sites with coronal circumferential defects: an experimental study in dogs

Objective: The study was designed to evaluate bone apposition around SLA (sandblasted, large-grit and acid-etched) implants compared with modified SLA (modSLA) ones at sites with different sizes of circumferential gaps.
Material and methods: All mandibular premolars and first molars of six beagle dogs were extracted. After a healing period of 3 months, three 10-mm-long implants were inserted in each side of the mandible. One implant was inserted with a 0.5-mm and one with a 1-mm gap between the implants and bone around the coronal 5 mm of the implants. The third implant was inserted without a gap as a control. The dogs were sacrificed respectively at weeks 2, 4 and 8 after implant placement for histological and histomorphometric analyses.
Results: The histomorphometric results showed similar pattern of bone apposition for the two surfaces. At 2 and 4 weeks of healing, the percentage of newly formed bone-to-implant contact (BIC%), new bone fill (NBF%) and the distance between the most coronal position of BIC and the defect bottom (B–D) were significantly higher for modSLA ( P <0.05). At 8 weeks of healing, this difference was not significant ( P >0.05). With regard to the defect size, the histological analyses showed no significant differences between the two defect sizes at all time points ( P >0.05).
Conclusion: Significantly more bone apposition was found for the modSLA surface than for the SLA surface at early stage of healing, indicating that modSLA surface may enhance bone apposition in coronal circumferential defects at non-submerged implants. Gap size within 1 mm may not need any kind of regenerative procedures.     

Influence of two barrier membranes on staged guided bone regeneration and osseointegration of titanium implants in dogs. Part 2: augmentation using bone graft substitutes

Objectives: To assess the influence of two barrier membranes and two bone graft substitutes on staged guided bone regeneration and osseointegration of titanium implants in dogs. Materials and methods: Saddle‐type defects were prepared in the lower jaws of 6 fox hounds and randomly filled with a natural bone mineral (NBM) and a biphasic calcium phosphate (SBC) and allocated to either an in situ gelling polyethylene glycol (PEG) or a collagen membrane (CM). At 8 weeks, modSLA titanium implants were inserted and left to heal in a submerged position. At 8+2 weeks, respectively, dissected blocks were processed for histomorphometrical analysis (e.g., mineralized tissue [MT], bone‐to‐implant contact [BIC]). Results: The mean MT values (mm²) and BIC values (%) tended to be higher in the PEG groups (MT: NBM [3.4±1.7]; SBC [4.2±2]/BIC: NBM [67.7±16.9]; SBC [66.9±17.8]) when compared with the corresponding CM groups (MT: NBM [2.5±0.8]; SBC [2.3±1.6]/BIC: NBM [54.1±22.6]; SBC [61±8.7]). These differences, however, did not reach statistical significance. Conclusion: It was concluded that all augmentation procedures investigated supported bone regeneration and staged osseointegration of modSLA titanium implants. To cite this article :
Mihatovic I, Becker J, Golubovic V, Hegewald A, Schwarz F. Influence of two barrier membranes on staged guided bone regeneration and osseointegration of titanium implants in dogs. Part 2: augmentation using bone graft substitutes.
Clin Oral Impl Res. 23 , 2012; 308–315.
doi: 10.1111/j.1600‐0501.2011.02238.x     

The effect of SLActive surface in guided bone formation in osteoporotic-like conditions

Objectives: The aim of the study was to evaluate new bone formation under etched titanium (SLA) and modified‐etched hydrophilic titanium (modSLA) domes placed on the calvarium of healthy, osteoporotic and osteoporotic treated with bisphosphonates rabbits. Methods: Experimental osteoporosis was induced by ovariectomy (OV) and calcium‐deficient diet in 24 New Zealand female rabbits. Twelve OV rabbits were treated with weekly dozes of alendronate (Fosamax^®) (B) while 12 OV rabbits received no treatment (O). Another 12 rabbits were sham operated and used as healthy controls (C). At 6 weeks following OV, one modSLA and one SLA titanium dome were placed in the parietal bones of each rabbit. The animals were sacrificed at 30 and 120 days following the dome placement. Various histomorphometric measurements were performed in the most central of the undecalcified sections produced. Results: After 30 days of healing, in the C group, the total bone (TB) area was 37.6% and 37.0% under the modSLA and SLA domes, respectively. In the O group, the TB was 35.7% and 24.8%. In the B group, TB was 37.0% and 32.1%, respectively. After 120 days of healing, in the C group TB was 40.1% and 36.4%, respectively. In the O group, TB was 29.6% and 27.9%, respectively. In the B group, TB was 49.7% and 42.5%, respectively. Hierarchical analysis of variance showed that the type of titanium dome significantly influenced new bone and the amount of new bone being in contact with inner surface of the dome (BIC) independently of the observation period and group (P<0.05). The administration of bisphosphonates influenced the BIC (P<0.05). Conclusion: The use of modSLA surface may promote bone healing and osseointegration in osteoporotic rabbits, whereas administration of bisphosphonates may compromise the osseointegration of the newly formed bone at the early healing period. To cite this article:
Mardas N, Schwarz F, Petrie A, Hakimi A‐R, Donos N. The effect of SLActive surface in guided bone formation in osteoporotic‐like conditions.
Clin. Oral Impl. Res. 22 , 2011; 406–415.
doi: 10.1111/j.1600‐0501.2010.02094.x     

Influence of two barrier membranes on staged guided bone regeneration and osseointegration of titanium implants in dogs: part 1. Augmentation using bone graft substitutes and autogenous bone

Objectives: To assess the influence of two barrier membranes and two bone graft substitutes mixed with autogenous bone (AB) on staged guided bone regeneration and osseointegration of titanium implants in dogs. Materials and methods: Four saddle‐type defects each were prepared in the upper jaw of six fox hounds and randomly filled with a natural bone mineral (NBM)+AB and a biphasic calcium phosphate (SBC)+AB and allocated to either an in situ gelling polyethylene glycol (PEG) or a collagen membrane (CM). At 8 weeks, modSLA titanium implants were inserted and left to heal in a submerged position. At 8+2 weeks, dissected blocks were processed for histomorphometrical analysis (e.g., treated area [TA], bone‐to‐implant contact [BIC]). Results: The mean TA values (mm²) and BIC values (%) tended to be higher in the PEG groups(TA: NBM+AB [10.4 ± 2.5]; SBC+AB [10.4 ± 5.8]/BIC: NBM+AB [86.4 ± 20.1]; SBC+AB [80.1 ± 21.5]) when compared with the corresponding CM groups (TA: NBM+AB [9.7 ± 4.8]; SBC+AB [7.8 ± 4.3]/BIC: NBM+AB [71.3 ± 20.8]; SBC+AB [72.4 ± 20.3]). A significant difference was observed for the mean TA values in the SBC+AB groups. Conclusion: It was concluded that all augmentation procedures investigated supported bone regeneration and staged osseointegration of modSLA titanium implants. However, the application of PEG may be associated with increased TA values. To cite this article:
Schwarz F, Mihatovic I, Golubovic V, Hegewald A, Becker J. Influence of two barrier membranes on staged guided bone regeneration and osseointegration of titanium implants in dogs: part 1. Augmentation using bone graft substitutes and autogenous bone.
Clin. Oral Impl. Res. 23 , 2012; 83–89.
doi: 10.1111/j.1600‐0501.2011.02187.x     

Factors influencing resonance frequency analysis assessed by Osstell™mentor during implant tissue integration: II. Implant surface modifications and implant diameter

Objectives: To monitor the development of the stability of Straumann^® tissue‐level implants during the early phases of healing by resonance frequency analysis (RFA) and to determine the influence of implant surface modification and diameter. Material and methods: A total of twenty‐five 10 mm length implants including 12 SLA RN ?4.1 mm implants, eight SLActive RN ?4.1 mm implants and five SLA WN ?4.8 mm implants were placed. Implant stability quotient (ISQ) values were determined with Osstell^?mentor at baseline, 4 days, 1, 2, 3, 4, 6, 8 and 12 weeks post‐surgery. ISQ values were compared between implant types using unpaired t‐tests and longitudinally within implant types using paired t‐tests. Results: During healing, ISQ decreased by 3–4 values after installation and reached the lowest values at 3 weeks. Following this, the ISQ values increased steadily for all implants and up to 12 weeks. No significant differences were noted over time. The longitudinal changes in the ISQ values showed the same patterns for SLA implants, SLActive implants and WB implants. At placement, the mean ISQ values were 72.6, 75.7 and 74.4, respectively. The mean lowest ISQ values, recorded at 3 weeks, were 69.9, 71.4 and 69.8, respectively. At 12 weeks, the mean ISQ values were 76.5, 78.8 and 77.8, respectively. The mean ISQ values at all observation periods did not differ significantly among the various types. Single ISQ values ranged from 55 to 84 during the entire healing period. Pocket probing depths of the implants ranged from 1 to 3 mm and bleeding on probing from 0 to 2 sites/implant post‐surgically. Conclusions: All ISQ values indicated the stability of Straumann^® implants over a 12‐week healing period. All implants showed a slight decrease after installation, with the lowest ISQ values being reached at 3 weeks. ISQ values were restored 8 weeks post‐surgically. It is recommended to monitor implant stability by RFA at 3 and 8 weeks post‐surgically. However, neither implant surface modifications (SLActive) nor implant diameter were revealed by RFA. To cite this article:
Han J, Lulic M, Lang NP. Factors influencing resonance frequency analysis assessed by Osstell^?mentor during implant tissue integration: II. Implant surface modifications and implant diameter.
Clin. Oral Impl. Res. 21 , 2010; 605–611.
doi: 10.1111/j.1600‐0501.2009.01909.x     

Osseointegration of commercial microstructured titanium implants incorporating magnesium: a histomorphometric study in rabbit cancellous bone

Objective: Recent studies have suggested that magnesium (Mg) ions exert a beneficial effect on implant osseointegration. This study assessed the osseointegration of nanoporous titanium (Ti) surface incorporating the Mg produced by hydrothermal treatment in rabbit cancellous bone to determine whether this surface would further enhance bone healing of moderately rough‐surfaced implants in cancellous bone, and compared the result with commercially available micro‐arc oxidized Mg‐incorporated implants. Material and methods: The Mg‐incorporated Ti surfaces (RBM/Mg) were obtained by hydrothermal treatment using an alkaline Mg‐containing solution on grit‐blasted moderately rough (RBM) implants. Untreated RBM and recently introduced Mg‐incorporated microporous Ti implants produced by micro‐arc oxidation (M) were used controls in this study. The surface characteristics were evaluated by scanning electron microscopy, X‐ray photoelectron spectroscopy and optical profilometry. Twenty‐four threaded implants with a length of 10 mm (eight RBM implants, eight RBM/Mg implants and eight M implants) were placed in the femoral condyles of 12 New Zealand White rabbits. Histomorphometric analysis was performed 4 weeks after implantation. Results: Hydrothermally treated and untreated grit‐blasted implants displayed almost identical surface morphologies and R_a values at the micron‐scale. The RBM/Mg implants exhibited morphological differences compared with the RBM implants at the nano‐scale, which displayed nanoporous surface structures. The Mg‐incorporated implants (RBM/Mg and M) exhibited more continuous bone apposition and a higher degree of bone‐to‐implant contact (BIC) than the untreated RBM implants in rabbit cancellous bone. The RBM/Mg implants displayed significantly greater BIC% than untreated RBM implants, both in terms of the all threads region and the total lateral length of implants (P<0.05), but no statistical differences were found between the RBM/Mg and M implants except BIC% values in total lateral length. Conclusion: These results indicate that a nanoporous Mg‐incorporated surface may be effective in enhancing the osseointegration of moderately rough grit‐blasted implants by increasing the degree of bone?implant contact in areas of cancellous bone. To cite this article :
Park J‐W, An C‐H, Jeong S‐H, Suh J‐Y. Osseointegration of commercial microstructured titanium implants incorporating magnesium: a histomorphometric study in rabbit cancellous bone.
Clin. Oral Impl. Res. 23 , 2012; 294–300.
doi: 10.1111/j.1600‐0501.2010.02144.x     

Stability change of chemically modified sandblasted/acid-etched titanium palatal implants. A randomized-controlled clinical trial

Aim: The aim of this randomized-controlled clinical study was to examine stability changes of palatal implants with chemically modified sandblasted/acid-etched (modSLA) titanium surface compared with a standard SLA surface, during the early stages of bone healing.
Materials and methods: Forty adult volunteers were recruited and randomly assigned to the test group (modSLA surface) and to the control group (SLA surface). The test and control implants had the same microscopic and macroscopic topography, but differed in surface chemistry. To document implant stability changes resonance frequency analysis (RFA) was performed at implant insertion, at 7, 14, 21, 28, 35, 42, 49, 56, 70 and 84 days thereafter. RFA values were expressed as an implant stability quotient (ISQ).
Results: Immediately after implant installation, the ISQ values for both surfaces tested were not significantly different and yielded mean values of 73.8±5 for the control and 72.7±3.9 for the test surface. In the first 2 weeks after implant installation, both groups showed only small changes and thereafter a decreasing trend in the mean ISQ levels. In the test group, after 28 days a tendency towards increasing ISQ values was observed and 42 days after surgery the ISQ values corresponded to those after implant insertion. For the SLA-control group, the trend changed after 35 days and yielded ISQ values corresponding to the baseline after 63 days. After 12 weeks of observation, the test surface yielded significantly higher stability values of 77.8±1.9 compared with the control implants of 74.5±3.9, respectively.
Conclusion: The results support the potential for chemical modification of the SLA surface to positively influence the biologic process of osseointegration and to decrease the healing time.     

Bone‐to‐Implant Contact Around Immediately Loaded Direct Laser Metal‐Forming Transitional Implants in Human Posterior Maxilla

Objective: Direct laser metal forming (DLMF) is a procedure in which a high‐power laser beam is directed onto a metal powder bed and programmed to fuse particles according to a computer‐aided design file, generating a thin metal layer. This histologic study evaluated the bone‐to‐implant contact (BIC%) around immediately loaded DLMF transitional implants retrieved after 2 months from posterior human maxillae. Methods: Twelve totally edentulous individuals (mean age, 66.14 ± 2.11 years) received DLMF transitional implants divided in twelve immediately loaded (IL) and twelve unloaded (UI) implants. These transitional implants were placed between conventional implants to support the interim complete maxillary denture during the healing period. After 8 weeks, the transitional implants and the surrounding tissue were removed and prepared for histomorphometric analysis. Results: Mature woven preexisting bone lined by newly formed bone in early stages of maturation were found around all retrieved implants. Histometric evaluation indicated that the mean BIC% was 45.20 ± 7.68% and 34.10 ± 7.85% for IL and UI, respectively (P <0.05). Conclusion: The present data obtained in humans showed that, although both IL and UI presented good BIC%, IL DLMF implants had a higher BIC% in the posterior maxilla.     

Relation between insertion torque and bone–implant contact percentage: an artificial bone study

Objectives

The purpose of this study was to determine the correlation between the peak insertion torque value (ITV) of a dental implant and the bone–implant contact percentage (BIC%).

Material and methods

Dental implants were inserted into specimens comprising a 2-mm-thick artificial cortical shell representing cortical bone and artificial foam bone representing cancellous bone with four densities (groups 1 to 4—0.32, 0.20, 0.16, and 0.12?g/cm³). Each specimen with an inserted implant was subjected to micro-computed tomography (micro-CT) scanning, from which the 3D BIC% values were calculated. Pearson’s correlation coefficients (r) between the ITV and BIC% were calculated.

Results

The ITVs in groups 1 to 4 were 56.2?±?4.6 (mean±standard deviation), 45.6?±?0.9, 43.3?±?4.3, and 38.5?±?3.4?N?cm, respectively, and the corresponding BIC% values were 41.5?±?0.5%, 39.0?±?1.0%, 30.8?±?1.1%, and 26.2?±?1.6%. Pearson’s correlation coefficient between the ITV and BIC% was r?=?0.797 (P?<?0.0001).

Conclusion

The initial implant stability, quantified as the ITV, was strongly positively correlated with the 3D BIC% obtained from micro-CT images.

Clinical relevance

The ITV of a dental implant can be used to predict the initial BIC%; this information may provide the clinician with important information on the optimal loading time.     

Histomorphometric analysis of the osseointegration of four different implant surfaces in the femoral epiphyses of rabbits

Objectives: The surface properties of titanium dental implants are key parameters for rapid and intimate bone–implant contact. The osseointegration of four implant surfaces was studied in the femoral epiphyses of rabbits. Material and methods: Titanium implants were either grit‐blasted with alumina or biphasic calcium phosphate (BCP) ceramic particles, coated with a thin octacalcium phosphate (OCP) layer, or prepared by large‐grit sand blasting and acid‐etched (SLA). After 2 and 8 weeks of implantation, the bone‐implant contact and bone growth inside the chambers were compared. Scanning electron microscopy (SEM) and profilometry showed distinct microtopographies. Results: The alumina‐Ti, BCP‐Ti and OCP‐Ti groups had similar average surface roughness in the 1–2 μm range whereas the SLA surface was significantly higher with a roughness averaging 4.5 μm. Concerning the osseointegration, the study demonstrated a significantly greater bone‐to‐implant contact for both the SLA and OCP‐Ti surfaces as compared with the grit‐blasted surfaces, alumina‐ and BCP‐Ti at both 2 and 8 weeks of healing. Conclusion: In this animal model, a biomimetic calcium phosphate coating gave similar osseointegration to the SLA surface. This biomimetic coating method may enhance the apposition of bone onto titanium dental implants.     

Early loading of single crowns supported by 6‐mm‐long implants with a moderately rough surface: a prospective 2‐year follow‐up cohort study

Aim: To evaluate prospectively the clinical and radiographic outcomes after 2 years of loading of 6 mm long moderately rough implants supporting single crowns in the posterior regions. Material and methods: Forty SLActive Straumann^® short (6 mm) implants were placed in 35 consecutively treated patients. Nineteen implants, 4.1 mm in diameter, and 21 implants, 4.8 mm in diameter, were installed. Implants were loaded after 6 weeks of healing. Implant survival rate, marginal bone loss and resonance frequency analysis (RFA) were evaluated at different intervals. The clinical crown/implant ratio was also calculated. Results: Two out of 40 implants were lost before loading. Hence, the survival rate before loading was 95%. No further technical or biological complications were encountered during the 2‐year follow‐up. The mean marginal bone loss before loading was 0.34±0.38 mm. After loading, the mean marginal bone loss was 0.23±0.33 and 0.21±0.39 mm at the 1‐ and 2‐year follow‐ups. The RFA values increased between insertion (70.2±9) and the 6‐week evaluation (74.8±6.1). The clinical crown/implant ratio increased with time from 1.5 at the delivery of the prosthesis to 1.8 after 2 years of loading. Conclusion: Short implants (6 mm) with a moderately rough surface loaded early (after 6 weeks) during healing yielded high implant survival rates and moderate loss of bone after 2 years of loading. Longer observation periods are needed to draw more definite conclusions on the reliability of short implants supporting single crowns. To cite this article:
Rossi F, Ricci E, Marchetti C, Lang NP, Botticelli D. Early loading of single crowns supported by 6‐mm‐long implants with a moderately rough surface: a prospective 2‐year follow‐up cohort study.
Clin. Oral Impl. Res. 21 , 2010; 937–943.
doi: 10.1111/j.1600‐0501.2010.01942.x     

Vertical Osteoconductive Characteristics of Titanium Implants with Calcium‐Phosphate‐Coated Surfaces – A Pilot Study in Rabbits

Introduction: Osteoconductive characteristics of different implant surface coatings are in the focus of current interest. The aim of the present study was to compare the vertical osteoconductivity at the implant shoulder of supracrestal inserted calcium‐phosphate coated implants (SLA‐CaP) with conventional sand‐blasted/acid‐etched (SLA) implants in a rabbit model. Materials and Methods: SLA‐CaP and SLA implants were inserted bilaterally in the mandible of four rabbits in a split‐mouth design. The implants were placed 2 mm supracrestal. After 3 weeks, at the left and right implant shoulder, the percentage of linear bone fill (PLF) as well as bone‐implant contact (BIC‐D) were determined. Results: After 3 weeks, newly formed woven bone could be found at the shoulder of the most of both surface‐treated implants (75%). PLF was significantly higher in SLA‐CaP implants (11.2% vs. 46.5%; n = 8, p = .008). BIC‐D was significantly increased in the SLA‐CaP implants (13.0% vs. 71.4%; n = 8, p < .001) as well. Conclusion: The results of this study show for the first time that calcium‐phosphate coated surfaces on supracrestal inserted implants have vertical osteoconductive characteristics and increase the bone‐implant contact at the implant shoulder significantly in a rabbit model. In clinical long‐term settings, these implants may contribute to a better vertical bone height.