Non-surgical treatment of mild to moderate peri-implantitis with an oscillating chitosan brush or a titanium curette-12-month follow-up of a multicenter randomized clinical trial.

OBJECTIVES: To study clinical and radiographic outcomes after non-surgical treatment of peri-implantitis using either an oscillating chitosan brush (OCB) or titanium curette (TC) and to observe changes in clinical signs of inflammation after repeated treatment. METHODS: Thirty-nine patients with dental implants (n = 39) presented with radiographic bone level (RBL) of 2-4 mm, bleeding index (BI) ≥ 2, and probing pocket depth (PPD) ≥ 4 mm were randomly assigned to mechanical debridement with OCB (test) or TC (control). Treatment was performed at baseline and repeated at 3, 6, and 9 months in cases with > 1 implant site with BI ≥ 1 and PPD≥4 mm. Blinded examiners recorded PPD, BI, pus, and plaque. The radiographic bone level change between baseline and 12 months was calculated. A multistate model was used to calculate transitions of BI. RESULTS: Thirty-one patients completed the study. Both groups exhibited a significant reduction in PPD, BI, and pus at 12 months compared to baseline. Radiographic analysis showed stable mean RBL in both groups at 12 months. There was no statistically significant difference in any of the parameters between the groups. CONCLUSIONS: Within the limitations of this 12-month multicenter randomized clinical trial, non-surgical treatment of peri-implantitis with OCB or TC showed no statistically significant differences between the groups. Clinical improvements and, in some cases, disease resolution, was observed in both groups. However, persistent inflammation was a common finding which further puts emphasis on the need for further treatment.

Nonsurgical Treatment of Peri-implantitis Using a Chitosan Brush with Adjunctive Chemical Decontaminants- A Retrospective Case Series.

PURPOSE: To evaluate the effect of a simple nonsurgical procedure for the treatment of peri-implantitis. MATERIALS AND METHODS: A total of 30 implants across 24 patients diagnosed with moderate to advanced peri-implantitis were treated using a chitosan brush with adjunctive chemicals, ie, 3% hydrogen peroxide and a tetracycline slurry. The treatment was performed a total of three times, with intervals of approximately 3 weeks. RESULTS: Results showed improvement in both the clinical attachment level (CAL) and bleeding on probing score between the baseline and the re-examinations between 9 months and up to 43 months (mean 26.8 months) after treatment. The mean CAL at baseline was 3.4 mm (range: 1 to 8 mm), while the mean CAL during the final examination was 1.4 mm (range: 0 to 5 mm), demonstrating a mean reduction of CAL of 2 mm (range: 1 to 7 mm; P < .001). Of the analyzed implant sites, 72% demonstrated radiographic signs of osseous defect fill varying between 0.1 and 2.2 mm (mean: 1.0 mm). CONCLUSION: The results show that this novel treatment strategy may serve as a nonsurgical alternative to reduce parameters of inflammation around implants with moderate to advanced peri-implantitis.

Non-surgical treatment of mild to moderate peri-implantitis using an oscillating chitosan brush or a titanium curette-A randomized multicentre controlled clinical trial.

OBJECTIVES: This prospective, parallel-group, examiner-blinded, multicentre, randomized, controlled clinical trial aimed to assess the efficacy of an oscillating chitosan brush (OCB) versus titanium curettes (TC) on clinical parameters in the non-surgical treatment of peri-implantitis. MATERIAL AND METHODS: In five dental specialist clinics, 39 patients with one implant with mild to moderate peri-implantitis, defined as 2-4 mm radiographic reduced bone level, bleeding index (BI) ≥ 2, and probing pocket depth (PPD) ≥ 4 mm were randomly allocated to test and control groups, receiving OCB or TC debridement, respectively. Treatment was performed at baseline and three months. PPD, BI, and Plaque index (PI) were measured at six sites per implant and recorded by five blinded examiners at baseline, one, three, and six month(s). Pus was recorded as present/not present. Changes in PPD and BI were compared between groups and analysed using multilevel partial ordinal and linear regression. RESULTS: Thirty-eight patients completed the study. Both groups showed significant reductions in PPD and BI at six months compared with baseline (p < .05). There was no statistically significant difference in PPD and BI changes between the groups. Eradication of peri-implant disease as defined was observed in 9.5% of cases in the OCB group and 5.9% in the TC group. CONCLUSIONS: Within the limitations of this six-month multicentre clinical trial, non-surgical treatment of peri-implantitis with OCB and TC showed no difference between the interventions. Eradication of disease was not predictable for any of the groups.

Treatment of residual pockets using an oscillating chitosan device versus regular curettes alone-A randomized, feasibility parallel-arm clinical trial.

BACKGROUND: A brush made of chitosan has shown to be an effective and harmless device for non-surgical treatment of mild to moderate peri-implantitis. To date, no study has evaluated the use of a chitosan brush in the non-surgical treatment of residual pockets in periodontal treatment. METHODS: Seventy-eight patients with periodontitis were included in this multicenter, randomized, examiner-blind clinical trial of 6 months duration. Patients with residual probing pocket depth (PPD) of ≥5 mm and ≤7 mm following previous active periodontal treatment were included. Patients were assigned either subgingival treatment with curettes (control) or an oscillating chitosan brush (test). Changes in bleeding on probing (BoP) and PPD between baseline and terminal evaluation at 6 months were evaluated. RESULTS: A significant reduction in both PPD and BoP was seen within both groups. There was no significant difference in BoP between test and control groups after 6 months, but the reduction in PPD was significantly improved in the test group (P ≤ 0.01). The combined outcome of no BOP and PPD ≤4 mm was significantly better in the test group (P ≤ 0.01). No adverse reactions were seen. CONCLUSION: Treatment of residual periodontal pockets (PPD = 5 to 7 mm) with a chitosan brush disclosed equal or better clinical results as compared to regular curettes. This study supports that a chitosan brush can be used for subgingival biofilm removal and soft tissue curretage in the treatment of periodontitis.

Impact of simultaneous placement of implant and block bone graft substitute: an in vivo peri-implant defect model.

BACKGROUND: Insufficient bone volume around an implant is a common obstacle when dental implant treatment is considered. Limited vertical or horizontal bone dimensions may lead to exposed implant threads following placement or a gap between the bone and implant. This is often addressed by bone augmentation procedures prior to or at the time of implant placement. This study evaluated bone healing when a synthetic TiO2 block scaffold was placed in circumferential peri-implant defects with buccal fenestrations. METHODS: The mandibular premolars were extracted and the alveolar bone left to heal for 4 weeks prior to implant placement in six minipigs. Two cylindrical defects were created in each hemi-mandible and were subsequent to implant placement allocated to treatment with either TiO2 scaffold or sham in a split mouth design. After 12 weeks of healing time, the samples were harvested. Microcomputed tomography (MicroCT) was used to investigate defect fill and integrity of the block scaffold. Distances from implant to bone in vertical and horizontal directions, percentage of bone to implant contact and defect fill were analysed by histology. RESULTS: MicroCT analysis demonstrated no differences between the groups for defect fill. Three of twelve scaffolds were partly fractured. At the buccal sites, histomorphometric analysis demonstrated higher bone fraction, higher percentage bone to implant contact and shorter distance from implant top to bone 0.5 mm lateral to implant surface in sham group as compared to the TiO2 group. CONCLUSIONS: This study demonstrated less bone formation with the use of TiO2 scaffold block in combination with implant placement in cylindrical defects with buccal bone fenestrations, as compared to sham sites.

Treatment of peri-implant mucositis with a chitosan brush-A pilot randomized clinical trial.

OBJECTIVE: This aim of this study was to evaluate a chitosan brush for the treatment of peri-implant mucositis. MATERIALS AND METHODS: A total of 11 patients with a combined total of 24 dental implants and who were diagnosed with peri-implant mucositis were included in this 6-month, split mouth, pilot clinical trial. Implants were randomly assigned to either treatment with a chitosan brush using an oscillating dental hand piece or treatment with titanium curettes. Supportive treatment was provided at 3 months. Two calibrated periodontists, blinded to treatment group, performed all examinations, including probing pocket depths (PPD) and bleeding on probing (mBoP). The changes in clinical parameters were compared between groups at 2 weeks, 4 weeks and 6 months. A Mann-Whitney U test with an alpha level of 0.05 was used for the statistical analyses. RESULTS: Both groups demonstrated significant reductions in mBoP between baseline and 6 months. The test implants treated with the chitosan brush had a better improvement in mBoP at 2 weeks and 4 weeks compared to the implants treated with the titanium curettes. The reduction in PPD was significantly better in the test group at 4 weeks. All implants had stable bone levels, as seen on radiographs between baseline and 6 months. CONCLUSION: Reduced signs of inflammation were seen in both groups 6 months after the baseline treatment and 3 months after maintenance. A chitosan brush seems to be a safe and efficient device for debridement of dental implants.

Porous titanium granules in the treatment of peri-implant osseous defects-a 7-year follow-up study.

BACKGROUND: A great number of different treatment protocols for peri-implantitis have been suggested but there is no consensus regarding the most effective intervention. The aim of the present study was to evaluate the long-term clinical and radiographic results from a study on peri-implant osseous defect reconstruction. Patients having participated in a randomized clinical study 7 years earlier were invited for a re-examination. The treatment procedures included open flap debridement (OFD) with or without defect reconstruction with porous titanium granules (PTGs). Clinical parameters (probing pocket depth and bleeding on probing) and radiographic measurements were registered. FINDINGS: Of the original 32 patients, 12 patients with 12 implants were finally examined after 7 years (7.3 years [6.7-8]). Patients had been maintained one to two times yearly. The PTG group showed a mean probing pocket depth of 4.3 mm ± 2.4 compared with 3.5 mm ± 1.2 in the OFD group, at the deepest site. The change between the 12 months and the 7-year examination was similar in both groups. Five of the test implants and five of the control implants had at least one site with positive bleeding on probing score. The mean radiographic defect depth change as compared to 12 months was an increase of 1.9 mm ± 2.0 in the PTG group and a mean radiographic defect depth increase of 1.3 mm ± 1.4 in the OFD group. Due to the small number of patients, a statistical analysis was not performed, but the results indicated a minimal difference in osseous defect depth as compared with baseline and between groups. No PTG exposed to the oral cavity was observed, but the graft particles were seemingly scattered in the peri-implant soft tissue. CONCLUSIONS: This long-term follow-up of surgical treatment of peri-implant osseous defects showed unpredictable results.

TiO2 scaffolds in peri-implant dehiscence defects: an experimental pilot study.

OBJECTIVES: The primary objective was to assess osseointegration of implants with dehiscence defects grafted with a TiO2 scaffold. The secondary objective was to assess the performance of the scaffold in terms of mechanical stability and bone fill. MATERIAL AND METHODS: Five minipigs had the mandibular premolars extracted. After healing, two dental implants (SLActive® , Institut Straumann AG, Basel, Switzerland) with associated semi-cylindrical dehiscence defects (Ø = 6 mm, height = 10 mm) were installed in each quadrant. The defects were grafted with test scaffolds (n = 10) or control autologous bone blocks (n = 10). After 3 months submerged healing, the pigs were euthanized and the sites analysed by microcomputed tomography and histology. RESULTS: Four minipigs were available for second stage surgery; (n = 9) experimental and (n = 7) control sites. The mean bone-to-implant contact on the defect side was 82% (±10%) and 79% (±11%) in the test and control groups respectively. The mean level of first bone-to-implant contact was more coronal on the defect side in the test group 3.2 mm (±0.4 mm) than in the control group 3.6 mm (±1.1 mm). The defect area occupied by bone within the extent of the scaffold varied, but averaged 37% (±14.6%) whereas the material itself occupied 7.4% (±3.5%). CONCLUSIONS: Within the limitations of the study, the results suggest that the novel synthetic scaffold material perform similar to the autologous bone block control with respect to implant osseointegration. The mechanical properties of the scaffold appeared sufficient to withstand clinical load in the present experimental model.

Maxillary sinus augmentation with porous titanium granules: a microcomputed tomography and histologic evaluation of human biopsy specimens.

PURPOSE: The aim of this study was to assess bone ingrowth into porous titanium granules used for maxillary sinus augmentation. MATERIALS AND METHODS: Eighteen biopsy specimens from 17 patients participating in a clinical trial on sinus augmentation using porous titanium granules (PTG) were received in the laboratory. The specimens (trephine cores of 4.5 mm) were obtained 6 months after PTG placement. After being embedded in methacrylate, the samples were scanned in a microcomputed tomography (micro-CT) scanner. Specimens were then cut along the long axis and central slices were ground to 70 µm before staining with hematoxylin and eosin. RESULTS: The micro-CT analysis demonstrated an average bone fill of 19% (standard deviation [SD] 5.8%), whereas the graft material occupied 22.7% (SD 4.7%). The volume of newly formed bone decreased with the distance from the residual bone of the sinus floor. Two-dimensional histomorphometric analysis demonstrated a mean area of new bone of 16.1% (SD 9.4%). The PTG alone occupied 25.9% of the total mean area (SD 6.1%). The newly formed bone consisted mainly of woven bone growing in close contact with the granules and bridging the intergranular space. The remaining area was occupied predominantly by nonmineralized connective tissue. There were no signs of inflammation in any of the biopsy specimens. CONCLUSIONS: After 6 months, new bone had formed at a similar rate and quality as has been reported for other well-recognized bone graft substitutes. The new bone formed in close contact with the PTG, suggesting that the material is osteoconductive.

Porous ceramic titanium dioxide scaffolds promote bone formation in rabbit peri-implant cortical defect model.

Titanium oxide (TiO2) scaffolds have previously been reported to exhibit very low mechanical strength. However, we have been able to produce a scaffold that features a high interconnectivity, a porosity of 91% and a compressive strength above 1.2 MPa. This study analyzed the in vivo performance of the porous TiO2 scaffolds in a peri-implant cortical defect model in the rabbit. After 8 weeks of healing, morphological microcomputed tomography analyses of the defects treated with the TiO2 scaffolds had significantly higher bone volume, bone surface and bone surface-to-volume ratio when compared to sham, both in the cortical and bone marrow compartment. No adverse effects, i.e. tissue necrosis or inflammation as measured by lactate dehydrogenase activity and real-time reverse transcription polymerase chain reaction analysis, were observed. Moreover, the scaffold did not hinder bone growth onto the adjacent cortical titanium implant. Histology clearly demonstrated new bone formation in the cortical sections of the defects and the presence of newly formed bone in close proximity to the scaffold surface and the surface of the adjacent Ti implant. Bone-to-material contact between the newly formed bone and the scaffold was observed in the histological sections. Islets of new bone were also present in the marrow compartment albeit in small amounts. In conclusion, the present investigation demonstrates that TiO2 scaffolds osseointegrate well and are a suitable scaffold for peri-implant bone healing and growth.

Chemical debridement of contaminated titanium surfaces: an in vitro study.

OBJECTIVE: To compare the efficacy of different chemical solutions when used for chemical debridement of biofilm contaminated titanium surfaces in an in-vitro experimental study. MATERIALS AND METHODS: Commercially pure titanium discs with a diameter of 6.2 mm and height of 2 mm, mirror-polished with a measured surface amplitude value SA = 0.037 µm ± 0.009 were used as test-surfaces. A biofilm was simulated with multi-layers of Staphylococcus epidermidis ATCC359844 covering the entire titanium surface. The chemical agents tested were: 3% H2O2, 0.2% Chlorhexidine, 24% EDTA-gel, 3% H2O2 mixed with 1.6 g/L TiO2 and sterile saline solution. The decontamination effect was evaluated by optical density analysis using spectrophotometry and with scanning electron microscopy (SEM) images of the remaining biofilm. RESULTS: The suspensions of 3% H2O2 and 1.6 g/L TiO2 or 3% H2O2 alone were the most effective in removing S. epidermidis biofilms (p < 0.05), whereas 0.2% chlorhexidine or 24% EDTA gel had no significant effects. SEM images of the remaining biofilms supported the quantitative results indicating the higher efficacy of 3% H2O2 and 1.6 g/L TiO2 or 3% H2O2 alone. It also revealed that EDTA, despite a non-significant effect on reducing the amount of established biofilms, was able to alter the biofilm architecture, as demonstrated by increased interspaced regions. CONCLUSIONS: In this in vitro study the decontamination potential of a suspension of 3% H2O2 and 1.6 g/L TiO2 or 3% H2O2 alone were encouraging. Whether such procedures would have a similar effect in vivo remains to be determined.

Dimensional Ridge Preservation with a Novel Highly Porous TiO(2) Scaffold: An Experimental Study in Minipigs.

Despite being considered noncritical size defects, extraction sockets often require the use of bone grafts or bone graft substitutes in order to facilitate a stable implant site with an aesthetically pleasing mucosal architecture and prosthetic reconstruction. In the present study, the effect of novel TiO(2) scaffolds on dimensional ridge preservation was evaluated following their placement into surgically modified extraction sockets in the premolar region of minipig mandibles. After six weeks of healing, the scaffolds were wellintegrated in the alveolar bone, and the convex shape of the alveolar crest was preserved. The scaffolds were found to partially preserve the dimensions of the native buccal and lingual bone walls adjacent to the defect site. A tendency towards more pronounced vertical ridge resorption, particularly in the buccal bone wall of the nongrafted alveoli, indicates that the TiO(2) scaffold may be used for suppressing the loss of bone that normally follows tooth extraction.

Bone formation in TiO2 bone scaffolds in extraction sockets of minipigs.

The osteoconductive capacity of TiO(2) scaffolds was investigated by analysing the bone ingrowth into the scaffold structure following their placement into surgically modified extraction sockets in Gottingen minipigs. Non-critical size defects were used in order to ensure sufficient bone regeneration for the evaluation of bone ingrowth to the porous scaffold structure, and sham sites were used as positive control. Microcomputed tomographic analysis revealed 73.6±11.1% of the available scaffold pore space to be occupied by newly formed bone tissue, and the volumetric bone mineral density of the regenerated bone was comparable to that of the native cortical bone. Furthermore, histological evidence of vascularization and the presence of bone lamellae surrounding some of the blood vessels were also observed within the inner regions of the scaffold, indicating that the highly interconnected pore structure of the TiO(2) scaffolds supports unobstructed formation of viable bone tissue within the entire scaffold structure. In addition, bone tissue was found to be in direct contact with 50.0±21.5% of the TiO(2) struts, demonstrating the good biocompatibility and osteoconductivity of the scaffold material.

Porous titanium granules in the surgical treatment of peri-implant osseous defects: a randomized clinical trial.

PURPOSE: Porous titanium granules (PTG) may have potential as an osteoconductive bone graft substitute to treat peri-implant osseous defects. The aim of this study was to analyze clinical and radiographic outcomes of peri-implant osseous defects after treatment with PTG. MATERIALS AND METHODS: This prospective, randomized, case-control, clinical 12-month study compared open-flap debridement and surface decontamination with titanium curettes and 24% ethylenediaminetetraacetic acid gel (n = 16) to the same protocol but with the addition of PTG (n = 16). One-, two-, and three-wall infrabony defects were included. Patients were given amoxicillin and metronidazole 3 days before surgery and for 7 days afterwards. Implants were submerged and allowed to heal for 6 months. Probing pocket depths, bleeding on probing, implant stability using resonance frequency analysis, and radiographic evaluation were performed at baseline and at 12 months. The threshold for significance was set at .05. RESULTS: Change in radiographic defect height and percent fill of the peri-implant osseous defect significantly favored patients treated with PTG. Both treatment modalities demonstrated significant improvements in probing pocket depth, but significant differences between groups were not observed. The PTG-treated implants showed an increase in implant stability quotient (ISQ) of 1.6 units, compared with a decrease of 0.7 ISQ for the control group. No adverse effects were associated with PTG treatment. CONCLUSIONS: Reconstruction with PTG resulted in significantly better radiographic peri-implant defect fill compared with controls; however, the results do not necessarily imply reosseointegration or osseointegration of PTG particles. Improvements in clinical parameters were seen in both groups, but no differences between groups were demonstrated.

Porous titanium granules in the treatment of mandibular Class II furcation defects: a consecutive case series.

BACKGROUND: The osteoconductive potential of titanium is interesting from the perspective of periodontal surgery and reconstitution of osseous defects. The aim of the present consecutive case series is to evaluate a surgical strategy based on the use of porous titanium granules (PTG) in the treatment of Class II buccal furcation defects in mandibular molars in humans. METHODS: Surgical intervention with PTG used as a bone graft substitute was performed in 10 patients with 10 mandibular Class II buccal furcation defects. Clinical parameters (probing depth (PD), clinical attachment level (CAL), gingival recession (GR), gingival index (GI), bleeding on probing (BOP), and horizontal and vertical bone sounding) and radiographic measurements of vertical furcation height were compared among baseline (presurgery), 6, and 12 months (post-surgery). The significance level (α) was set at 0.05. RESULTS: With respect to vertical and horizontal bone sounding measurements, CAL, and GR, no significant improvements between baseline and the 12-month examination were seen. Both PD and radiographic vertical furcation height were significantly reduced between baseline and 12 months. When comparing the baseline to 12-month data, a significantly lower GI score was seen but the BOP score was unchanged. None of the treated teeth showed radiographic signs of root resorption. CONCLUSION: This study suggests that PTG is safe to use in close proximity to root surfaces, but no significant improvements in clinical endpoints of defect resolution were observed.

The effect of permanent grafting materials on the preservation of the buccal bone plate after tooth extraction: an experimental study in the dog.

OBJECTIVES: The aim of the present study was to evaluate the effects of a novel bone substitute system (Natix(®)), consisting of porous titanium granules (PTG) and a bovine-derived xenograft (Bio-Oss(®)), on hard tissue remodelling following their placement into fresh extraction sockets in dogs. MATERIAL AND METHODS: Six modalities were tested; Natix(®) granules with and without a covering double-layered Bio Gide(®) membrane; Bio-Oss(®) with and without a covering double-layered Bio Gide(®) membrane; and a socket left empty with and without a covering double-layered Bio Gide(®) membrane. Linear measurements, indicative of buccal bone height loss, and an area measurement indicative of buccal bulk bone loss were made. The statistical analysis was based on the Latin Square design with two blocking factors (dog and site). Tukey's post hoc test was used to adjust for multiple comparisons. RESULTS: Histological observation revealed that while bone formed around both the xenograft and the titanium particles, bone was also noted within titanium granules. Of the five modalities of ridge preservation techniques used in this study, no one technique proved to be superior. CONCLUSION: The titanium granules were observed to have promising osseoconductive properties.

Micro CT and human histological analysis of a peri-implant osseous defect grafted with porous titanium granules: a case report.

Treatment of peri-implant osseous defects represents a significant challenge for clinicians, and the need to evolve within predictable surgical procedures is important. This case report describes the surgical treatment and grafting with porous titanium granules (PTG) of one patient with a peri-implant osseous defect. The suggested thrombogenic properties of titanium are intriguing from the perspective of osseous reconstructive surgery. In an ongoing randomized clinical trial using PTG for treatment of peri-implant osseous defects, one patient with one test implant was excluded and scheduled for implant removal. The surgical therapy included open flap debridement with surface decontamination with 24% EDTA gel, grafting with PTG, and resubmersion of the implant. After 12 months of healing, the implant with surrounding tissues was excised en bloc and micro CT and histological analyses were performed. Analyses showed PTG in close contact with new bone and with bone growing both into the porosities of the graft material and onto the adjacent implant surface. Element analysis demonstrated calcium and phosphorus in the new tissue embedding the PTG and the implant. Int J Oral Maxillofac Implants 2011;26:e9-e14.

Porous titanium granules promote bone healing and growth in rabbit tibia peri-implant osseous defects.

OBJECTIVES: The aim of this study was to investigate the osteoconductive properties and biological performance of porous titanium granules used in osseous defects adjacent to titanium implants. MATERIAL AND METHODS: In this animal experimental study, calibrated defects were prepared in the tibias of 24 New Zealand rabbits. The defects were randomized into two tests and one control group. The test defects were grafted with either metallic or oxidized porous titanium granules (PTG or WPTG, respectively), whereas control defects were left empty (sham). The defects were closed with a submerged coin shaped titanium implant. Defects were left for healing for 4 weeks. After healing, the implants were removed and the new bone tissue formed onto the implant surface was analyzed for run x 2, osteocalcin, collagen-I, tartrate-resistant acid phosphatase, H(+)-ATPase, tumor necrosis factor-alpha, interleukin (IL)-6 and IL-10 gene expression using reverse transcriptase polymerase chain reaction. Wound fluid from the healed defects was analyzed for lactate dehydrogenase and alkaline phosphatase activity. Finally osteoconductivity was analyzed by micro-computed tomography and histology. RESULTS: Significantly more new bone formed in PTG and WPTG grafted defects compared with sham. The new bone grew both through the porosities of the granules and onto the implant surfaces. The WPTG group showed significantly less expression of key inflammation markers, but with no significant difference in a marker for necrosis. The WPTG also showed a significant increase in collagen-I mRNA expression compared with PTG. CONCLUSION: The results suggest that PTG and WPTG are both osteoconductive materials that can be used to promote bone formation in osseous defects adjacent to titanium implants without hampering implant osseointegration.

In vivo performance of absorbable collagen sponges with rosuvastatin in critical-size cortical bone defects.

Rosuvastatin (RSV) is a synthetic statin with favourable pharmacologic properties, but its local effect in bone has yet to be investigated. The aim of this study was to evaluate the potential of absorbable collagen sponge (ACS) as a carrier for RSV to enhance bone formation in critical-size cortical bone defects adjacent to titanium implants. ACS, treated with different concentrations of RSV (R1 = 8.7 + or - 1.8 microg; R2 = 52.0 + or - 4.4 microg; R3 = 259.1 + or - 8.8 microg) or phosphate-buffered saline alone, were placed into the bone marrow through a defect made in the proximal tibial cortical bone of New Zealand White rabbits. One empty defect (SHAM) served as an internal control in each animal. After a healing time of 4 weeks, a concentration-dependent increase of alkaline phosphatase activity in ACS treated with RSV was detected in the bone fluid after removing the implants. In addition, a significant concentration-dependent increase in BMP-2 mRNA levels was found in the cortical bone tissue adjacent to the RSV-treated ACS. The cortical architecture of bone defects analysed by micro-computed tomography showed a trend towards higher bone volume in the ACS+R1 group compared with SHAM, which was accompanied by an increase in the bone mineral density. Evaluation of histological sections showed new bone formation in ACS treated with RSV but not in untreated ACS. These results indicate that RSV, when administered locally in bone, may have a potential effect in stimulating bone formation.