Combining Scaffolds and Osteogenic Cells in Regenerative Bone Surgery: A Preliminary Histological Report in Human Maxillary Sinus Augmentation

Purpose: The following case series evaluated the maxillary sinus augmentation responses to tissue-engineered bone graft obtained by a culture of autogenous osteoblasts seeded on polyglycolic–polylactic scaffolds and calcium phosphate.
Materials and Methods: Sinus floor augmentation was performed bilaterally in five patients (mean age 58.4 years) with tissue-engineered bone (test site – Oral Bone®, BioTissue, Freiburg, Germany) or calcium phosphate (control site – Biocoral, Novaxa Spa, Milan, Italy). Biopsies were harvested 6 months after sinus augmentation for histometric evaluation. Volumetric measurements were taken at baseline and 6 months after the surgical procedure.
Results: The mean of vertical bone gain was 6.47 ± 1.39 mm and 9.14 ± 1.19 mm to test and control sites, respectively. The histological sections depicted mature bone with compact and cancellous areas. All biopsies contained varying percentages of newly formed bone and marrow spaces. The mean of bone tissue in the grafted area was 37.32 ± 19.59% and 54.65 ± 21.17% for tissue-engineered bone and calcium phosphate, respectively.
Conclusion: Within the limits of the present report, the histological data in humans confirmed that tissue-engineered bone and calcium phosphate allowed newly formed bone after maxillary sinus augmentation.     

A Lateral Approach for Sinus Elevation Using PRGF Technology

Purpose: A lateral approach for sinus elevation using plasma rich in growth factors (PRGF) technology is described. The long-term survival of dental implants installed following a two-stage procedure after sinus elevation using this procedure is reported, using implant loss as the outcome variable.
Materials and Methods: A retrospective cohort study design was used. Eighteen patients received 43 implants (BTI implants, Biotechnology Institute, Vitoria, Spain) with sinus floor elevation. All patients presented a residual bone height of class D (1–3 mm). Implants were installed using a low-speed drilling procedure (50 rpm) without irrigation. Finally, the histological and histomorphometric evaluation of eight samples from PRGF grafted sinus involved in the study was carried out 5–6 months posttreatment.
Results: The overall survival rate of dental implants was 100%. The mean follow-up period for all implants was 33 ± 7 months ranging from 24 to 44 months. In addition, the histomorphometrical evaluation of the samples evidenced a 25.24 ± 4.62% of vital newly formed bone, 50.31 ± 15.56% of soft connective tissue, and the remaining 24.46 ± 12.79% of bovine anorganic bone.
Conclusions: Based on these results, this new approach for sinus elevation and implant installation using PRGF technology can be considered safe, simple, effective, and predictable.     

Osteotome sinus floor elevation technique without grafting material: 3-year results of a prospective pilot study

Objective: In a prospective pilot study, short≤10 mm ITI-SLA implants were placed in the resorbed posterior maxilla by means of an osteotome sinus floor elevation (OSFE) procedure without grafting material. This paper presents 3-year data assessing bone-level changes around implants.
Material and methods: Twenty-five implants were placed in 17 patients to rehabilitate 16 molar and nine premolar sites. The mean residual bone height (RBH) was 5.4 ± 2.3 mm. A healing period of 3–4 months was allowed before abutment tightening. Most implants (21/25) were 10 mm long, and the others were 8 and 6 mm long. At the 3-year control, endo-sinus bone gain, implant length protruding into the sinus and crestal bone loss (CBL) were measured on periapical radiographs.
Results: All implants fulfilled the survival criteria. Despite the absence of grafting material, implants were embedded into newly formed bone tissue. All implants gained endo-sinus bone; the mean gained bone was 3.1 ± 1.5 mm. The residual protrusion length decreased from 4.9 ± 2.1 to 1.8 ± 2.1 mm. CBL was 0.9 ± 0.8 mm.
Conclusions: This study confirms that the OSFE procedure without grafting material is sufficient to create bone beyond the natural limit of the sinus. On the mid-term of 3 years, the technique was found to be predictable in the posterior maxilla when the RBH is limited. Implants gained endo-sinus bone despite the lack of grafting material. Bone gain was still improving over the first-year control. No shrinkage of the augmented area was observed.     

Effect of calcium phosphate surface coating on bone ingrowth onto porous-surfaced titanium alloy implants in rabbit tibiae.

PURPOSE: The purpose of the present study was to determine whether calcium phosphate coating has a significant impact on bone ingrowth into a porous titanium implant. MATERIALS AND METHODS: Porous-surfaced titanium alloy Ti-6Al-4V implants were prepared with or without the addition of a thin surface layer of calcium phosphate applied by sol-gel coating. Implants were placed into the tibiae of 16 rabbits. Implanted sites were allowed to heal for 2 weeks, after which specimens were retrieved for morphometric assessment using backscatter scanning electron microscopy. RESULTS: The data collected show that there is more extensive ingrowth into the porous regions of the calcium phosphate-coated implants than into the control implants. The weighted average ingrowth for the calcium phosphate-coated implants was 2.01, whereas that for the noncoated implants was 1.49; the difference is statistically significant (P <.01). CONCLUSIONS: The addition of a thin layer of calcium phosphate to these implants appears to promote a more extensive implant-to-bone interface by allowing the neck regions to become intimately ingrown with bone even after only 2 weeks of initial healing.     

Bone formation in transforming growth factor beta-I-loaded titanium fiber mesh implants

The osteoconductive properties of porous titanium (Ti) fiber mesh with or without a calcium phosphate (Ca-P) coating and osteoinductive properties of noncoated Ti fiber mesh loaded with recombinant human Transforming Growth Factor beta-1 (rhTGF-beta1) were investigated in a rabbit non-critical size cranial defect model. Nine Ca-P-coated and 18 non-coated porous titanium implants, half of them loaded with rhTGF-beta1, were bilaterally placed in the cranium of 18 New Zealand White rabbits. At 8 weeks postoperative, the rabbits were sacrificed and the skulls with the implants were retrieved. Histological analysis demonstrated that in the TGF-beta1-loaded implants, bone had been formed throughout the implant, up to its center, whereas in the non-loaded implants only partial ingrowth of bone was observed. Bone formation had a trabecular appearance together with bone marrow-like tissue. No difference in ingrowth could be observed between the non-TGF-beta1-loaded non-coated implants and the Ca-P-coated ones. All histological findings were confirmed by image analysis: 97% ingrowth was seen in the rhTGF-beta1-loaded implants, while only 57% and 54% ingrowth was observed in the non-loaded Ca-P-coated and non-coated implants, respectively. Bone surface area and bone fill were significantly higher in the rhTGF-beta1-loaded implants (1.37 mm2 and 36%, respectively) than in the non-loaded implants (0.57 mm2 and 26%). No statistical difference was found for any parameter between the Ca-P-coated and noncoated implants. Quadruple fluorochrome labeling showed that in the Ti and Ti-CaP implants mainly bone guidance had occurred from the former defect edge, while in the Ti-TGF-beta1 implants bone formation had mainly started in the center of a pore and proceeded in a centrifugal manner. Our results show that: (1) the combination of Timesh with TGF-beta1 can induce orthotopic bone formation; (2) Ti-fiber mesh has good osteoconductive properties; (3) a thin Ca-P coating, as applied in this study, does not seem to further enhance the bone-conducting properties of a titanium scaffold material.     

Which region of the median palate is a suitable location of temporary orthodontic anchorage devices? A histomorphometric study on human cadavers aged 15–20 years

Introduction: Endosseus implants can provide a reliable anchorage during orthodontic treatment. The midpalatal structures around the sutura palatina mediana (SPM) are of special interest due to increasing placement of orthodontic implants in this area. Knowledge about the osseous conditions at this site is necessary to predict the expected degree of implant osseointegration.
Methods: The upper jaws of 10 human cadavers, aged 15–20 years, were decalcified, and cross-sectional specimens were obtained from four anterior-to-posterior palatal regions for histomorphometric analysis. The analyses focused on the amount of bone and the width of the SPM to determine the anatomical requirements for reliable insertion of palatal implants.
Results: Bone density [bone-volume (BV)/ tissue-volume (TV)] in all measured areas was 40–60%. The maximum density was measured at the level of the first premolars (54.9±5.9%) and the least values (44.2±9.6%) were measured at the level of the interconnecting line of the canines. The mean width of the SPM varies from 1.2 to 0.3 mm in different sections of the palate. In the median sagittal plane, the mean values of bone height to nasal cavity reached >5 mm as far as the level distal of the second premolars. Bone height 2 mm paramedian to the SPM decreased consistently from anterior (4.3±0.9 mm) to posterior (2.5±0.8 mm).
Conclusions: Our results indicate that the amount and quality of bone along the anterior palatal midline in 15-to-20-year olds is sufficient for orthodontic implantation. Even implantation posterior to the recommended first premolar level, at which orthodontic implants are most often placed, may be suitable. There are some limitations, however, due to small number of samples and variations of anatomical structures.     

Biphasic calcium phosphate ceramics in small bone defects: potential influence of carrier substances and bone marrow on bone regeneration

Objectives: Synthetic calcium phosphate bone substitutes such as hydroxyapatite (HA), β-tricalcium phosphate (β-TCP) or mixtures are alternatives to autogenous bone grafts. TricOs T^® and Collagraft^® are resorbable bone substitutes consisting of biphasic calcium phosphate and a bioactive matrix. Both products have a similar HA to β-TCP ratio, but differ by their matrix. It was the aim of this study to determine the influence of matrix and autologous bone marrow on bone regeneration in a rabbit femoral condyle model.
Material and methods: A critical-sized bicortical channel with a diameter of 4.5 mm was drilled through the femoral condyles in male New Zealand rabbits. Collagraft^® with bone marrow harvested from the posterior iliac crest or TricOs T^® with and without bone marrow was introduced into the defect. Rabbits were euthanized 8 weeks later. The percentage of newly formed bone was determined by micro-computed tomography.
Results: There was no significant difference between bone ingrowth at 8 weeks. Thus, TricOs T^® without bone marrow showed similar bone ingrowth as Collagraft^® with bone marrow. Furthermore, no increase of bone ingrowth could be achieved by adding bone marrow to TricOs T^® in the present setting.
Conclusion: Both bone substitutes showed similar bone ingrowth in this investigation. Using TricOs T^® without bone marrow could avoid donor site morbidity due to harvesting of bone marrow. Further prospective clinical trials will be needed to investigate this approach.     

Implant system for guiding a new layer of bone. Computed microtomography and histomorphometric analysis in the rabbit mandible

Objective: To prove the concept that an implant system with osteoconductive surface characteristics and an osteoinductive scaffold material has the capacity to guide vertical supracrestal bone growth in a rabbit mandible onlay model.
Material and methods: Thirteen adult white New Zealand rabbits each received custom-designed dental implants. All implants had sandblasted, acid-etched (SLA^™) surfaces, with the coronal aspect (3 mm) of each implant was left outside the lateral aspect of posterior mandibular bone, but covered by periosteum, muscle, subcutaneous tissue, and skin. Bone formation around implants placed adjacent to osteoinductive demineralized bone matrix (DBM) scaffolds were compared with contralateral implants without scaffolds in six rabbits using micro-CT imaging. Bone formation around implants with scaffolds from seven additional rabbits was measured using both micro-CT imaging and quantitative histology.
Results: At 8 weeks, new supracrestal bone was seen adjacent to all implants placed with DBM and two implants without DBM. The mean supracrestal bone heights achieved for implants with and without DBM scaffolds as measured by micro-CT was 2.1±0.9 and 0.8±0.9 mm, respectively ( P =0.008). Histomorphometric analysis illustrated that supracrestal bone-to-implant contact for implants with DBM scaffolds was 58.1±14% and that mean supracrestal bone height was 2.4±0.6 mm.
Conclusions: Successful implant-guided supracrestal osteogenesis has been demonstrated in a rabbit model with the combined use of osteoconductive implant surfaces, an osteoinductive scaffold, and a device that prevents soft tissue downgrowth and provides scaffold stabilization.     

Histomorphometric Analysis of Human Maxillary Sinus Lift with a New Bone Substitute Biocomposite: A Preliminary Report

Purpose: To analyze radiographic and histological outcomes of maxillary sinus floor augmentation using a calcium-sulfate based allograft containing demineralized bone matrix particles.
Materials and Methods: Fifteen maxillary sinus lift procedures with simultaneous placement of titanium implants were performed in 12 patients of both genders aged 36–71 years. Each sinus cavity was filled by the biocomposite. After 3 months of healing, all surgical sites were uncovered and bone biopsies were retrieved for undecalcified histology and histomorphometry. The ratio between the original and the grafted sinus height (GSH/OSH) was computed using a panoramic radiography taken immediately after surgery and at 3 months of healing, and the two ratios were compared by Wilcoxon signed-rank test.
Results: By 3 months, all implants were stable without clinical and radiographic signs of infection. Significant changes in GSH/OSH during healing were seen (2.7 ± 0.6 initially vs. 2.6 ± 0.5 after healing; p  = 0.01). Histologic findings showed newly formed bone surrounding the residual grafted particles without inflammation. At 3 months, mean regenerated bone density was 33.8 ± 8.6%; marrow spaces amounted to 32.3 ± 10.3%; residual graft was 33.9 ± 9.0%. Similar histomorphometric and radiographic results were obtained independently from patient age or sex.
Conclusions: The analysed putty seems to be a safe and effective graft material for maxillary sinus floor augmentation by accelerating bone regeneration and thus reducing the healing time.     

Influence of defect depth on resonance frequency analysis and insertion torque values for implants placed in fresh extraction sockets: a human cadaver study

Background: Clinical studies show promising outcomes with implants inserted at the time of extraction. However, this often results in an initial bone defect at the marginal region which preferably should heal for an optimal function. Therefore, monitoring of these implants is vital.
Purposes: The aims of this study were to determine the initial stability of implants placed into fresh extraction sockets, and to explore the correlations between the peri-implant bone levels and implant stability parameters.
Materials and Methods: Six human cadaver mandibles including all natural teeth were selected for this study. All natural teeth were gently extracted, and 84 implants were immediately placed into fresh extraction sockets with five different implant depths. The maximum insertion torque values were recorded, and primary implant stability measurements were performed by means of resonance frequency analysis (RFA). The vertical distance between implant/abutment junction and the first bone–implant contact was recorded using a periodontal probe.
Results: It was found that the insertion torque and RFA were 28.9 ± 7 Ncm and 65.6 ± 9 implant stability quotient (ISQ), respectively, for 420 measurements from all 84 implants. Statistically significant correlation was found between insertion torque and ISQ values ( r  = 0.86; p  < .001) for all implants. Both insertion torque and ISQ values dramatically decreased when the amount of peri-implant vertical bone defect increased.
Conclusion: The results of this study demonstrated a linear relationship between peri-implant vertical bone defect depth and RFA value. It is proposed that the RFA method is sensitive to detect changes of the marginal bone level and may be used to monitor healing of peri-implant bone defects.     

Ridge augmentation and maxillary sinus grafting with a biphasic calcium phosphate: histologic and histomorphometric observations

Objectives: This retrospective study reports on histologic and histomorphometric observations performed on human biopsies harvested from sites augmented exclusively by biphasic calcium phosphate [BCP: hydroxyapatite (HA)/ tricalcium phosphate (TCP) 60/40] and healed for a minimum of 6 months.
Materials and methods: Five patients benefited from three augmentation regimens (i.e.: one-stage lateral augmentation; two-stage lateral augmentation; and two-stage sinus grafting). In all patients, a degradable collagen membrane served as a cell-occlusive barrier. Core biopsies were obtained from lateral as from crestal aspects 6–10 months after augmentation surgeries. For histologic and histomorphometric evaluations, the non-decalcified tissue processing was performed.
Results: The histological examination of 11 biopsies showed graft particles frequently being bridged by the new bone, and a close contact between the graft particles and newly formed bone was seen in all samples. The mean percentages of newly formed bone, soft tissue compartment, and graft material were 38.8% (±5.89%), 41.75% (±6.08%), and 19.63% (±4.85%), respectively. Regarding bone-to-graft contact values, the percentage of bone coverage of graft particles for all biopsies ranged from 27.83% to 80.17%. The mean percentage of bone coverage was 55.39% (±13.03%).
Conclusions: Data from the present study demonstrated osteoconductivity scores for the BCP material (HA/TCP 60/40) in patients resembling those previously shown for grafting materials of xenogenic and alloplastic origin.     

Biomechanical aspects of primary implant stability: a human cadaver study

Background: The quality of bone is an important factor in the successful implant treatment, and it is evident that higher implant failure is more likely in poor quality of bone. The primary stability of oral implants related to resistance to micromotion during healing is influenced by bone quality, surgical technique, and implant design.
Purposes: The aims of this biomechanical study were to explore the effect of bone quality on initial intraosseous stability of implants, and to determine the correlations between the bone quality and implant stability parameters.
Materials and Methods: Twenty-four implants (Neoss Ltd., Mölnlycke, Sweden) were placed into anterior and posterior regions of three human cadaver mandibles. The bone densities of implant recipient sites were preoperatively determined using computerized tomography (CT) in Hounsfield unit (HU). The maximum insertion torque values were recorded, and primary implant stability measurements were noninvasively performed by means of resonance frequency analysis (RFA).
Results: The bone density values ranged from −267 HU to 553 HU. It was found that mean bone density, insertion torque, and RFA values were 113 ± 270 HU, 41.9 ± 5 Ncm, and 70 ± 7 implant stability quotient (ISQ), respectively. Statistically significant correlations were found between bone density and insertion torque values ( r  = 0.690, p  < .001); bone density and ISQ values ( r  = 0.557, p  < .05); and insertion torque and ISQ values ( r  = 0.853, p  < .001).
Conclusion: CT is a useful tool to assess bone quantity and quality in implant recipient sites, and bone density has a prevailing effect on implant stability at placement.     

Influence of the surgical technique and surface roughness on the primary stability of an implant in artificial bone with a density equivalent to maxillary bone: a laboratory study

Objective: The aim of this biomechanical study was to assess the effect of surgical technique and surface roughness on primary implant stability in low-density bone.
Material and methods: Eighty screw-shaped (Biocomp^®) implants with machined or etched surface topography were inserted into a low-density bone equivalent. Solid rigid polyurethane blocks (Sawbones^®) with two different bone densities (group A=0.32 g/cm³; group B=0.48 g/cm³) were used that are very similar to the density of the maxilla. The implant sites were prepared either by a press-fit or by an undersized technique. Peak insertion and removal torques were measured using a Digital^® torque gauge instrument.
Results: Independent of the surgical technique used, both implant types showed an increased mean insertion and removal torque value with increasing bone density. Insertion and removal torque values were 54.3±5.3 and 43.5±6.5 N cm for group A and 89.3±7.6 and 55±9.1 for group B, respectively. For group A and B, both implant types showed statistically higher insertion and removal torque mean values for the undersized compared with the press-fit technique ( P <0.01). In addition, etched implants showed statistically higher insertion and removal torque mean values compared with machined implants ( P <0.01).
Conclusion: The placement of etched implants in synthetic bone models using an undersized preparation technique resulted in enhanced primary implant stability; further, a correlation was found between primary stability and bone density of the synthetic bone, implying that in case of an implant site with low bone density, by changing the surgical technique and choosing an implant with an optimal surface roughness, the primary stability can be enhanced significantly.     

Evaluation of nano-technology-modified zirconia oral implants: a study in rabbits

Objective: The objective of this study was to screen candidate nano-technology-modified, micro-structured zirconia implant surfaces relative to local bone formation and osseointegration.
Materials and Methods: Proprietary nano-technology surface-modified (calcium phosphate: CaP) micro-structured zirconia implants (A and C), control micro-structured zirconia implants (ZiUnite™), and titanium porous oxide implants (TiUnite™) were implanted into the femoral condyle in 40 adult male New Zealand White rabbits. Each animal received one implant in each hind leg; thus, 20 animals received A and C implants and 20 animals received ZiUnite™ and TiUnite™ implants in contralateral hind legs. Ten animals/group were euthanized at weeks 3 and 6 when biopsies of the implant sites were processed for histometric analysis using digital photomicrographs produced using backscatter scanning electron microscopy.
Results: The TiUnite™ surface demonstrated significantly greater bone–implant contact (BIC) (77.6±2.6%) compared with the A (64.6±3.6%) and C (62.2±3.1%) surfaces at 3 weeks ( p <0.05). Numerical differences between ZiUnite™ (70.5±3.1%) and A and C surfaces did not reach statistical significance ( p >0.05). Similarly, there were non-significant differences between the TiUnite™ and the ZiUnite™ surfaces ( p >0.05). At 6 weeks, there were no significant differences in BIC between the TiUnite™ (67.1±4.2%), ZiUnite™ (69.7±5.7%), A (68.6±1.9%), and C (64.5±4.1%) surfaces ( p >0.05).
Conclusion: TiUnite™ and ZiUnite™ implant surfaces exhibit high levels of osseointegration that, in this model, confirm their advanced osteoconductive properties. Addition of CaP nano-technology to the ZiUnite™ surface does not enhance the already advanced osteoconductivity displayed by the TiUnite™ and ZiUnite™ implant surfaces.     

Long-term effects of magnetron-sputtered calcium phosphate coating on osseointegration of dental implants in non-human primates

Objectives: To determine the effect of magnetron-sputtered calcium phosphate coating of implants on the later stages of osseointegration in a non-human primate model.
Material and methods: Eighteen and 20 implants with a 0.1 μm amorphous calcium phosphate coating and a turned surface, respectively, were inserted in the anterior upper and lower jaw of adult non-human primates. Following a 7.5 months healing period, one part of the implants remained in the submerged position. The other part of implants was connected to healing abutments to allow peri-implant inflammation to occur. After another 20 months, histologic and histomorphometric analysis of the peri-implant area was performed.
Results: Submerged implants with a calcium phosphate coating and a turned surface showed no signs of an inflammatory reaction. The histomorphometric parameters 'bone volume per tissue volume' (BV/TV) and 'bone-to-implant contacts' (BIC) were not affected by calcium phosphate coating. Non-submerged implants of both groups showed occasionally signs of inflammation at the implant–abutment junction. Histomorphometric analysis revealed that the distance between the implant–abutment junction and the most coronal level (where bone was attached to the implant) as well as BV/TV and BIC were independent from the surface modification.
Conclusion: Our results show that dental implants with calcium phosphate coating behave similar to turned implants independently whether they are connected to healing abutments or remain submerged. Ultra-thin calcium phosphate coating can combine the positive effects of calcium phosphate during the early stage of osseointegration without causing impairment of the later stages.     

A clinical study evaluating the treatment of supra-alveolar-type defects with access flap surgery with and without an enamel matrix protein derivative: a pilot study

Aim: There is evidence that regenerative treatment of intra-bony and mandibular class II furcation defects with access flap and an application of an enamel matrix protein derivative (EMD) can result in a clinical benefit compared with access flap alone. The aim of this pilot study was to check if the results of access flap surgery in suprabony defects are improved by additional application of EMD.
Material and Methods: Thirty-nine adult subjects with supra-alveolar-type defects were randomly assigned to a test ( n =25) and a control group ( n =14). Seventy teeth were treated with EMD; 28 teeth were treated by access flap. Probing depth (PD), clinical attachment level and bleeding on probing were evaluated at baseline and after 12 months.
Results: PD of the operated teeth was improved in both groups ( p <0.001 to p =0.041) but always better in the test group. The attachment gain was 2.72±1.80 mm at sites with an initial PD 7 mm in the test group and 0.78±0.62 mm in the control group ( p =0.004). In the test group the mean attachment gain was 0.97±0.92 mm ( p <0.001); the mean reduction of PD was 1.55±0.90 mm ( p <0.001).
Conclusions: The data suggest a significant clinical benefit of supplementary application of EMD during surgical treatment of periodontitis of supra-alveolar pockets, especially in deeper pockets.     

Induction of bone formation by Escherichia coli-expressed recombinant human bone morphogenetic protein-2 using block-type macroporous biphasic calcium phosphate in orthotopic and ectopic rat models

Park J‐C, So S‐S, Jung I‐H, Yun J‐H, Choi S‐H, Cho K‐S, Kim C‐S. Induction of bone formation by Escherichia coli‐expressed recombinant human bone morphogenetic protein‐2 using block‐type macroporous biphasic calcium phosphate in orthotopic and ectopic rat models. J Periodont Res 2011; 46: 682–690. © 2011 John Wiley & Sons A/S Background and Objective: The potential of the Escherichia coli‐expressed recombinant human bone morphogenetic protein‐2 (ErhBMP‐2) to support new bone formation/maturation using a block‐type of macroporous biphasic calcium phosphate (bMBCP) carrier was evaluated in an orthotopic and ectopic rat model. Material and Methods: Critical‐size (Φ 8 mm) calvarial defects and subcutaneous pockets in 32 Sprague–Dawley rats received implants of rhBMP‐2 (2.5 μg) in a bMBCP carrier or bMBCP alone (control). Implant sites were evaluated using histological and histometric analysis following 2‐ and 8‐wk healing intervals (eight animals/group/interval). Results: ErhBMP‐2/bMBCP supported significantly greater bone formation at 2 and 8 wk (10.8% and 25.4%, respectively) than the control at 2 and 8 wk (5.3% and 14.0%, respectively) in calvarial defects (p < 0.01). Bone formation was only observed for the ErhBMP‐2/bMBCP ectopic sites and was significantly greater at 8 wk (7.5%) than at 2 wk (4.5%) (p < 0.01). Appositional and endochondral bone formation was usually associated with a significant increase in fatty marrow at 8 wk. The bMBCP carrier showed no evidence of bioresorption. Conclusion: ErhBMP‐2/bMBCP induced significant bone formation in both calvarial and ectopic sites. Further study appears to be required to evaluate the relevance of the bMBCP carrier.     

Regenerative treatment with platelet-rich plasma combined with a bovine-derived xenograft in smokers and non-smokers: 12-month clinical and radiographic results

Aim: The purpose of this study was to assess the healing response of intrabony defects following regenerative treatment with platelet-rich plasma (PRP) combined with a bovine-derived xenograft (BDX) in smokers and non-smokers.
Materials and Methods: A total of 24 advanced chronic periodontitis patients, 12 smokers and 12 non-smokers, with 113 intrabony defects with an intrabony component of 3 mm were included in this study. Defects were surgically treated with PRP/BDX. At baseline and 12 months after surgery, the following parameters were recorded: plaque and sulcus bleeding indices, probing depth (PD), relative attachment level, marginal recession, probing and radiographic bone levels.
Results: Considering the soft tissue measurements, smokers and non-smokers presented a mean PD reduction of 3.97 ± 0.76 and 4.63 ± 0.52 mm, recession of 0.76 ± 0.44 and 0.50 ± 0.12 mm and attachment gain of 3.26 ± 0.42 and 4.06 ± 0.40 mm, respectively. Evaluation of the hard tissue findings revealed that the mean clinical and radiographic bone gains in smokers and non-smokers were 2.83 ± 0.47 and 3.63 ± 0.38 mm, 2.98 ± 0.38 and 3.67 ± 0.48 mm, respectively. Inter-group differences for PD reduction ( p <0.05), attachment ( p <0.001), clinical ( p <0.001) and radiographic bone gains ( p <0.001) were found to be significant between smokers and non-smokers.
Conclusions: Within the limits of this study, the results indicate that treatment outcome following PRP/BDX application in intrabony defects is impaired with smoking.     

Stability of crestal bone level at platform-switched non-submerged titanium implants: a histomorphometrical study in dogs

Objectives: To investigate the influence of platform switching on crestal bone level changes at non-submerged titanium implants over a period of 6 months.
Material and Methods: Titanium implants ( n =72) were placed at 0.4 mm above the alveolar crest in the lower jaws of 12 dogs and randomly assigned to either matching or non-matching (circumferential horizontal mismatch of 0.3 mm) healing abutments. At 4, 8, 12, and 24 weeks, dissected blocks were processed for histomorphometrical analysis. Measurements were made between the implant shoulder (IS) and the apical extension of the long junctional epithelium (aJE), the most coronal level of bone in contact with the implant (CLB), and the level of the alveolar bone crest (BC).
Results: At 24 weeks, differences in the mean IS–aJE, IS–CLB, and IS–BC values were 0.2 ± 1.2, 0.3 ± 0.7, and 0.3 ± 0.8 mm at the buccal aspect, and 0.2 ± 0.9, 0.3 ± 0.5, and 0.3 ± 0.8 mm at the lingual aspect, respectively. Comparisons between groups revealed no significant differences at either the buccal or the lingual aspects.
Conclusions: It was concluded that (i) bone remodelling was minimal in both groups and (ii) platform switching may not be of crucial importance for maintenance of the crestal bone level.     

Ten-year results following treatment of intra-bony defects with enamel matrix proteins and guided tissue regeneration

Background: Surgery utilizing an enamel matrix protein derivative (EMD) or guided tissue regeneration (GTR) has been shown to promote periodontal regeneration.
Aim: To evaluate the 10-year results following treatment with EMD, GTR, EMD+GTR, and open flap debridement (OFD).
Material and Methods: Thirty-eight patients out of an initial group of 56 participants were treated with one of the four modalities. Results were evaluated before surgery, at 1 year, and at 10 years. Primary outcome variable was CAL change.
Results: Treatment with EMD yielded a mean CAL gain of 3.4±1.0 mm ( p <0.001) and 2.9±1.4 mm ( p <0.001) at 1 and 10 years, respectively. GTR resulted in a mean CAL gain of 3.2±1.4 ( p <0.001) at 1 year and 2.8±1.2 mm ( p <0.001) at 10 years. Mean CAL gain in the EMD+GTR group was of 3.3±1.1 mm ( p <0.001) and 2.9±1.2 mm ( p <0.001) at 1 and 10 years, respectively. Treatment with OFD demonstrated a mean CAL gain of 2.0±1.2 mm ( p <0.01) at 1 year and 1.8±1.1 mm ( p <0.01) at 10 years. Compared with OFD, the three regenerative treatments resulted in statistically significant ( p <0.05) higher CAL gain, at both 1 and 10 years. The CAL change between 1 and 10 years did not present statistically significant differences in any of the four groups.
Conclusion: The present results indicate that the clinical outcomes obtained with all four approaches can be maintained over a period of 10 years.