Sinus augmentation analysis revised: the gradient of graft consolidation

Objective: Graft consolidation follows a gradient that reflects the properties of bone substitutes at sites of sinus augmentation. Here we present an analytical method to investigate the process of graft consolidation taking the distance from the maxillary host bone into account. Material and methods: We therefore evaluated histological specimens, 6 and 12 weeks after the sinus of minipigs was augmented with Bio‐Oss^®, a deproteinized bovine bone mineral, and Ostim^®, an aqueous paste of synthetic nanoparticular hydroxyapatite. A curve was drawn that represents the changes in histomorphometric parameters within a given distance from the maxillary host bone. Results: Based on this curve, three regions of interest were defined: R1 (0–1 mm) the bridging distance where new bone is laid onto the host bone, R2 (2–3 mm) a region of osteoconduction where new bone exclusively grows on the biomaterial, R3 (4–5 mm) and a region of osteoconduction where bone formation has reached its maximal extension. Qualitative and quantitative analysis of the three regions can reveal differences in graft consolidation, depending on the bone substitutes and the observation period [Bone volume (BV) per tissue volume after 6 weeks: R1: 19±8.4% for Bio‐Oss^® and 42.9±13.2% for Ostim^® (P=0.03), R2: 3±2.4% for Bio‐Oss^® and 14.7±9.5% for Ostim^® (P=0.03), R3: 5±4.1% for Bio‐Oss^® and 5.3±5.3% for Ostim^® (P=0.86). BV per tissue volume after 12 weeks: R1: 38.0±13.3% for Bio‐Oss^® and 53.3±6.6 for Ostim^® (P=0.04), R2: 14±12.2 for Bio‐Oss^® and 26.4±11 for Ostim^® (P=0.18), R3: 6.6±7 for Bio‐Oss^® and 10.7±5.8 for Ostim^® (P=0.32) after 12 weeks]. Conclusion: Based on the graft consolidation gradient, the impact of bone substitutes to modulate the process of bone formation and the kinetic of degradation within a distinct region of the augmented sinus can be investigated.     

Effect of grafting materials on osseointegration of dental implants surrounded by circumferential bone defects. An experimental study in the dog

Aims: This study was designed to evaluate the effect of gap width and graft placement on bone healing around implants placed into simulated extraction sockets in the mandibles of four beagle dogs. Materials and methods: Four Ti‐Unite^® implants (13 mm × 3.3 mm) were placed on each side of the mandible. Three implants were surrounded by a 1.35 mm circumferential and a 5 mm deep gap around the coronal portion of the implants. A fourth implant was inserted conventionally into both sides of the mandibles as a positive control. The gaps were filled with either Bio‐Oss^®, autogenous bone or with a blood clot alone. The study design was balanced for animal, side and modality. Ground sections were prepared from biopsies taken at 3 months, and computer‐aided histometric measurements of bone/implant contact and area of bone within threads were made for the coronal 5 mm. Data were analysed using analysis of variance. Results: The mean bone/implant contact was 9.8 mm for the control and ranged from 9.3 to 11.3 mm for the three test modalities. The corresponding values for area within threads were 1 mm² and 1–1.2 mm². Modality had a significant effect on both bone/implant contact (F=16.9; P<0.0001) and area within threads (F=16.7; P<0.0001). Conclusion: The results of this study suggest that both autogenous bone graft and Bio‐Oss^® played an important role in the amount of hard tissue fill and osseointegration occurring within marginal bone defects around implants.     

Bone healing around implants placed in a jaw defect augmented with Bio-Oss. An experimental study in dogs

The present experiment was carried out to study some tissue reactions around implants that were placed in an edentulous ridge which had been augmented with deproteinized natural bovine cancellous bone mineral. In 4 male beagle dogs, the premolars in the right side of the mandible were extracted and a large buccal ridge defect was created by mechanical means. The bone plate at the lingual aspect of the defect was left intact. 5 months later, the distal 2/3 of the defect area was augmented with Bio‐Oss^® (Geistlich Sons Ltd, Wolhusen, Switzerland) mixed with a fibrin sealer (Tisseel^®, Immuno AG, Vienna, Austria). After 3 months of healing, 3 fixtures (Astra Tech AB, Mölndal, Sweden; TiO‐blast; 8×3.5 mm) were installed in the mandible; 2 were placed in the augmented portion and 1 was placed in the non‐augmented portion of the defect. After a healing period of 3 months, abutment connection was performed and a plaque control period initiated. 4 months later, the dogs were sacrificed and each implant region was dissected. The tissue samples were dehydrated, embedded in plastic, sectioned in the bucco‐lingual plane and examined in the light microscope. It was observed that osseointegration failed to occur to implant surfaces within an alveolar ridge portion previously augmented with Bio‐Oss^®. In the augmented portion of the crest, the graft particles were separated from the host tissue as well as from the implant by a well‐defined connective tissue capsule. Although the lingual aspect of all fixtures (test and control) was in contact with hard tissue at the time of installation, after 4 months of function, a deep vertical bone defect frequently had formed at the lingual surface of the implants. It was concluded that in this model (i) Bio‐Oss^® failed to integrate with the host bone tissue and (ii) no osseointegration occurred to the implants within the augmented portion of the crest.     

Effect of Bio-Oss with or without platelet-derived growth factor on bone formation by "guided tissue regeneration": a pilot study in rats

Aim: To investigate the effect of Bio‐Oss^® with and without the local application of recombinant human platelet‐derived growth factor (rhPDGF‐BB) on bone formation under Teflon capsules. Materials and Methods: Eight male, 6‐month‐old, Wistar strain rats were used in the study. In each animal, the lateral aspect of the mandibular ramus was exposed and small perforations were produced in the bone. A rigid, non‐porous hemispherical teflon capsule (diameter 7 mm) was placed on the ramus in both sides of the animals. The capsule placed on the one side of the jaw was filled with Bio‐Oss^® granules soaked in a solution of PDGF‐BB (20 μg/capsule) and autogenous blood prior to placement. The capsules placed on the other side of the jaw were filled with Bio‐Oss^® granules soaked in autogenous blood only (controls). Four rats were sacrificed after 3 months and the remaining four after 5 months. Undecalcified sections containing the capsule and surrounding tissues were prepared and analysed in the microscope. Results: Histologic analysis revealed limited amounts of bone formation. Most of the space underneath the capsules was occupied by Bio‐Oss^® particles surrounded by fibrovascular connective tissue. Given the small sample size statistical analysis was not possible, however, the mean amount of mineralized new bone in the control group (20.8%) appeared to be larger than that in the test group (6.7%). After 5 months the amount of newly formed bone appeared similar in the two groups (23.0% test, 26.0% controls). The Bio‐Oss^® particles occupied between 31.4% and 41.1% of the capsule area at 3 months and between 34.0% and 34.7% at 5 months. Only particles adjacent to the mandibular ramus were incorporated in newly formed bone. Conclusion: Limited bone formation was present in the capsules grafted with Bio‐Oss^® with or without the growth factor.     

Bio-Oss collagen in the buccal gap at immediate implants: a 6-month study in the dog

Background: Following tooth extraction and immediate implant installation, the edentulous site of the alveolar process undergoes substantial bone modeling and the ridge dimensions are reduced. Objective: The objective of the present experiment was to determine whether the process of bone modeling following tooth extraction and immediate implant placement was influenced by the placement of a xenogenic graft in the void that occurred between the implant and the walls of the fresh extraction socket. Material and methods: Five beagle dogs about 1 year old were used. The 4th premolar in both quadrants of the mandible (₄P₄) were selected and used as experimental sites. The premolars were hemi‐sected and the distal roots removed and, subsequently, implants were inserted in the distal sockets. In one side of the jaw, the marginal buccal‐approximal void that consistently occurred between the implant and the socket walls was grafted with Bio‐Oss^® Collagen while no grafting was performed in the contra‐lateral sites. After 6 months of healing, biopsies from each experimental site were obtained and prepared for histological analyses. Results: The outline of the marginal hard tissue of the control sites was markedly different from that of the grafted sites. Thus, while the buccal bone crest in the grafted sites was comparatively thick and located at or close to the SLA border, the corresponding crest at the control sites was thinner and located a varying distance below SLA border. Conclusions: It was demonstrated that the placement of Bio‐Oss^® Collagen in the void between the implant and the buccal‐approximal bone walls of fresh extraction sockets modified the process of hard tissue healing, provided additional amounts of hard tissue at the entrance of the previous socket and improved the level of marginal bone‐to‐implant contact. To cite this article:
Araújo MG, Linder E, Lindhe J. Bio‐Oss^® Collagen in the buccal gap at immediate implants: a 6‐month study in the dog.
Clin. Oral Impl. Res. 22 , 2011; 1–8.
doi: 10.1111/j.1600‐0501.2010.01920.x     

The effects of bone grafting material and a collagen membrane in the ridge splitting technique: an experimental study in dogs

Objectives: This study was designed to evaluate the effect of bone graft materials and collagen membranes in ridge splitting procedures with immediate implant placement using a dog model. Materials and methods: Mandibular premolars were extracted in five beagle dogs. After 3 months, ridge splitting and placement of three OsseoSpeed^? implants were performed bilaterally. The gaps between the implants were allocated according to the following eight treatment modalities; Group 1(no graft), Group 2 (autogenous bone), Group 3 (Bio‐Oss^® Collagen), Group 4 (Bio‐Oss^®), Group 5 (no graft+BioGide^®), Group 6 (autogenous bone+BioGide^®), Group 7 (Bio‐Oss^® Collagen+BioGide^®), and Group 8 (Bio‐Oss^®+BioGide^®). The dogs were sacrificed after 8 or 12 weeks and the specimens were analyzed histologically and histometrically. Results: The gaps between the implants were filled with the newly formed bone, irrespective of which of the eight grafting techniques was used. Group 1 revealed a significantly lower percentage of bone‐to‐implant contact (BIC) than Group 5 at 8 and 12 weeks (P<0.05). Group 1 showed the most prominent marginal bone loss (MBL) at 12 weeks (P<0.05). Regarding the use of membranes, Groups 1 and 2 showed significantly more MBL than Groups 5 and 6 at 12 weeks (P<0.05). Conclusions: After ridge splitting, if the gaps between implants were grafted or covered with collagen membranes, a higher percentage of BIC was obtained. Based on our results, we suggest that the use of bone graft materials and/or collagen membranes is better for the prevention of MBL after ridge splitting procedures. To cite this article:
Han J‐Y, Shin S‐I, Herr Y, Kwon Y‐H, Chung J‐H. The effects of bone grafting material and a collagen membrane in the ridge splitting technique: an experimental study in dogs.
Clin. Oral Impl. Res. xx , 2011; 000–000
doi: 10.1111/j.1600‐0501.2010.02127.x     

Guided bone generation in a rabbit mandible model after periosteal expansion with an osmotic tissue expander

Objectives: To evaluate the space‐maintaining capacity of titanium mesh covered by a collagen membrane after soft tissue expansion on the lateral border of the mandible in rabbits, and to assess bone quantity and quality using autogenous particulate bone or bone‐substitute (Bio‐Oss^®), and if soft tissue ingrowth can be avoided by covering the mesh with a collagen membrane. Material and methods: In 11 rabbits, a self‐inflatable soft tissue expander was placed under the lateral mandibular periosteum via an extra‐oral approach. After 2 weeks, the expanders were removed and a particulated onlay bone graft and deproteinized bovine bone mineral (DBBM) (Bio‐Oss^®) were placed in the expanded area and covered by a titanium mesh. The bone and DBBM were separated in two compartments under the mesh with a collagen membrane in between. The mesh was then covered with a collagen membrane. After 3 months, the animals were sacrificed and specimens were collected for histology. Results: The osmotic soft tissue expander created a subperiosteal pocket and a ridge of new bone formed at the edges of the expanded periosteum in all sites. After the healing period of 3 months, no soft tissue dehiscence was recorded. The mean bone fill was 58.1±18% in the bone grafted area and 56.9±13.7% in the DBBM area. There was no significant difference between the autologous bone graft and the DDBM under the titanium mesh with regard to the total bone area or the mineralized bone area. Scanning electron microscopy showed that new bone was growing in direct contact with the DBBM particles and the titanium mesh. There is a soft tissue ingrowth even after soft tissue expansion and protection of the titanium mesh with a collagen membrane. Conclusion: This study confirms that an osmotic soft tissue expander creates a surplus of periosteum and soft tissue, and that new bone can subsequently be generated under a titanium mesh with the use of an autologous bone graft or DBBM. To cite this article:
Abrahamsson P, Isaksson S, Andersson G. Guided bone generation in a rabbit mandible model after periosteal expansion with an osmotic tissue expander.
Clin. Oral Impl. Res. 22 , 2011; 1282–1288.
doi: 10.1111/j.1600‐0501.2010.02108.x     

Maxillary sinus augmentation using xenogenic bone substitute material Bio-Oss in combination with venous blood. A histologic and histomorphometric study in humans

The aim of the present study was to evaluate bone formation following maxillary sinus augmentation using bovine bone substitute material Bio‐Oss^® in combination with venous blood by means of histologic and histomorphometric examination of human biopsies. This involved a total of 15 sinus floor elevation procedures being carried out on 11 patients (average age of 49.6 years) according to the technique described by Tatum (1986). The subantral sinus cavity was augmented using bovine apatite combined with venous blood. After an average healing phase of 6.8 months, trephine burrs were used to take 22 bone biopsies from the augmented sinus region. Then 38 Brånemark^® implants were inserted in both the osteotomies resulting from bone sampling and in regular sites in the augmented posterior maxilla. Histomorphometric analysis of ground sections from the bone biopsies prepared according to the standard method of Donath & Breuner (1982) produced an average percentage of newly‐formed bone of 14.7% (±5.0%) and a proportion of residual xenogenic bone substitute material of 29.7% (±7.8%). Some 29.1% (±8.1%) of the surface of the Bio‐Oss^® granulate was in direct contact with newly‐formed bone. Histologically, newly‐developed bone became evident, partly invaginating the particles of apatite and forming bridges in the form of trabeculae between the individual Bio‐Oss^® particles. Despite the absence of osteoclastic activity, the inward growth of bone indicates slow resorption of the xenogenic bone graft material. When the implants were uncovered, after an average healing phase of 6 months, 4 of the 38 implants had become loose. Of these 4 implants, 1 had to be subsequently explanted, while the others remained as “sleeping implants” and were not included in the implants superstructure. Thus, the resulting clinical survival rate, prior to prosthetic loading, was 89.5%.     

Accelerated Photo‐Induced Hydrophilicity Promotes Osseointegration: An Animal Study

Background: In the previous in vitro study, fluoride‐modified, anodized porous titanium was proven to have enhanced its photo‐induced hydrophilicity, which induced the hyperactivation of initial cell response. Purpose: The purpose of the present study was to investigate in vivo bone apposition during the early stages of osseointegration in rabbit tibiae. Materials and Methods: Anodized porous titanium implants (TiU, TiUnite®, Nobel Biocare AB, Göteborg, Sweden) were modified with 0.175 wt% ammonium hydrogen fluoride solution (NH₄F‐HF₂). Twenty‐four hours prior to the experiments, the surface‐modified implants were ultraviolet‐irradiated (modTiU). Blinded and unpackaged TiU implants were used as controls. Thereafter, the implants were placed in the rabbit tibial metaphyses and histomorphometrically analyzed at 2 and 6 weeks after insertion. Results: ModTiU demonstrated a significantly greater degree of bone‐to‐metal contact than TiU after 2 and 6 weeks of healing. Conclusion: The results proved that the enhanced photo‐induced hydrophilicity of the NH₄F‐HF₂‐modified anodized implants promoted bone apposition during the early stages of osseointegration.     

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. To cite this article:
Bashara H, Wohlfahrt JC, Polyzois I, Lyngstadaas SP, Renvert S, Claffey N. The effect of permanent grafting materials on the preservation of the buccal bone plate after tooth extraction: an experimental study in the dog.
Clin. Oral Impl. Res. 23 , 2012; 911–917
doi: 10.1111/j.1600‐0501.2011.02240.x     

Dynamics of Bio‐Oss® Collagen incorporation in fresh extraction wounds: an experimental study in the dog

Aim: The objective of this experiment was to analyze processes involved in the incorporation of Bio‐Oss^® Collagen in host tissue during healing following tooth extraction and grafting. Methods: Five beagle dogs were used. Four premolars in the mandible (₃P₃, ₄P₄) were hemi‐sected, the distal roots were removed and the fresh extraction socket filled with Bio‐Oss^® Collagen. The mucosa was mobilized and the extraction site was closed with interrupted sutures. The tooth extraction and grafting procedures were scheduled in such a way that biopsies representing 1 and 3 days, as well as 1, 2 and 4 weeks of healing could be obtained. The dogs were euthanized and perfused with a fixative. Each experimental site, including the distal socket area, was dissected. The sites were decalcified in EDTA, and serial sections representing the central part of the socket were prepared in the mesio‐distal plane and parallel with the long axis of the extraction socket. Sections were stained in hematoxylin and eosin and were used for the overall characteristics of the tissues in the extraction socket. In specimens representing 1, 2 and 4 weeks of healing the various tissue elements were assessed using a morphometric point counting procedure. Tissue elements such as cells, fibers, vessels, leukocytes and mineralized bone were determined. In deparaffinized sections structures and cells positive for tartrate‐resistant acid phosphatase activity (TRAP), alkaline phosphatase and osteopontin were identified. Results: The biomaterial was first trapped in the fibrin network of the coagulum. Neutrophilic leukocytes [polymorphonuclear (PMN) cells] migrated to the surface of the foreign particles. In a second phase the PMN cells were replaced by multinuclear TRAP‐positive cells (osteoclasts). The osteoclasts apparently removed material from the surface of the xenogeneic graft. When after 1–2 weeks the osteoclasts disappeared from the Bio‐Oss^® granules they were followed by osteoblasts that laid down bone mineral in the collagen bundles of the provisional matrix. In this third phase the Bio‐Oss^® particles became osseointegrated. Conclusions: It was demonstrated that the incorporation of Bio‐Oss^® in the tissue that formed in an extraction wound involved a series of different processes. To cite this article:
Araújo MG, Liljenberg B, Lindhe J. Dynamics of Bio‐Oss^® Collagen incorporation in fresh extraction wounds: an experimental study in the dog.
Clin. Oral Impl. Res. 21 , 2010; 55–64.     

Transmucosal healing around peri‐implant defects: crestal and subcrestal implant placement in dogs

Objective: This study was designed to evaluate the transmucosal healing response of implants placed with the junction of the smooth surfaces, either crestal or subcrestal, into simulated extraction defects after healing periods of 1 and 3 months. Materials and methods: A total of 23 Straumann SP ?3.3 mm NN, SLA^® 10 mm implants were placed in the mandibular premolar regions of three greyhound dogs 3 months after the teeth were removed. Five control implants were placed at the crestal bone level, and test implants with surgically created peri‐implant defects of 1.25 mm wide × 5 mm depth were placed either at the crestal (nine implants) or at the 2 mm subcrestal (nine implants) bone level. Implants on the right side were placed 1 month before the dogs were sacrificed, and implants on the left side were placed 3 months before sacrifice. All dogs had daily plaque control following surgery and were sacrificed 3 months after implant placement for histological and histometric analyses. Results: Mesial–distal ground sections of the control and test implant specimens showed a greater %BIC in the coronal defect region after 3 months of healing. This healing response was incomplete for the test implants compared with the control implants after a 1‐month healing period. The histometric measurements for test implants placed at the crestal bone level or 2 mm subcrestal with surgically created peri‐implant defects were more coronal or closer to the implant margin compared with the control implants. Additionally, the degree of osseointegration between the newly formed bone and the implant surface was similar between the test implants. Conclusion: Peri‐implant defects of 1.25 mm width healed with spontaneous bone regeneration around implants placed transmucosally at crestal or 2 mm subcrestal with a high degree of osseointegration after a 3‐month healing period. To cite this article:
Tran BLT, Chen ST, Caiafa A, Davies HMS, Darby IB. Transmucosal healing around peri‐implant defects: crestal and subcrestal implant placement in dogs.
Clin. Oral Impl. Res. 21 , 2010; 794–803.
doi: 10.1111/j.1600‐0501.2010.01911.x     

Early Healing of Hydroxyapatite‐Coated Implants in Grafted Bone of Zoledronic Acid–Treated Osteoporotic Rabbits

Background: Resorption of grafted bone and delayed osseointegration of implants are main problems associated with alveolar bone augmentation in dental implantology, especially for patients with osteoporosis. The aim of this study is to investigate the early healing response of implants to systemic treatment of zoledronic acid (ZA) in autogenous grafted iliac bone of osteoporotic rabbits. Methods: Ovariectomy (OVX) or sham operation was performed in 46 rabbits, and osteoporotic changes were verified in animals receiving OVX 3 months later. The remaining animals were divided into three groups (n = 12): sham, OVX, and OVX with ZA treatment (ZA group). Autogenous iliac bone grafting was performed in bilateral tibiae, and hydroxyapatite‐coated titanium implants were simultaneously placed into the grafted bone. The animals were sacrificed 2 and 8 weeks later for examination. Results: At both time points, systemic treatment of ZA efficiently promoted bone healing of implants in grafted bone, and all histologic and microcomputed tomography bone indices, including mineralized bone volume, implant–bone contact ratio, connectivity density, trabecular thickness, and trabecular number, were significantly increased in the ZA group compared with the OVX‐only group (P <0.01); implant–bone contact rates in the ZA group were even restored to levels similar to those of sham‐operated animals (P >0.05). Furthermore, biomechanical testing demonstrated that removal torque of implants was significantly increased in the ZA group compared with the OVX group (P <0.01). Conclusion: Systemic treatment with ZA could efficiently promote early bone healing of implants in autogenous grafted bone of osteoporotic rabbits by increasing early osseointegration and fixation of implants.     

Ridge alterations following immediate implant placement and the treatment of bone defects with Bio-Oss in an animal model

Background: Conflicting data exist on the outcome of placing Bio‐Oss® (Geitslich Pharm AG, Wolhausen, Switzerland) into extraction sockets. It is therefore relevant to study whether the incorporation of Bio‐Oss into extraction sockets would influence bone healing outcome at the extraction sites. Purpose: The aim of this study was to assess peri‐implant bone changes when implants were placed in fresh extraction sockets and the remaining defects were filled with Bio‐Oss particles in a canine mandible model. Materials and Methods: Six mongrel dogs were used in the study. In one jaw quadrant of each animal, the fourth mandibular premolars were extracted with an elevation of the mucoperiosteal flap; implants were then placed in the fresh extraction sockets and the remaining defects were filled with Bio‐Oss particles. After 4 months of healing, micro‐computed tomography at the implant sites was performed. Osseointegration was calculated as the percent of implant surface in contact with bone. Additionally, bone height was measured in the peri‐implant bone. Results: Average osseointegration was 28.5% (ranged between 14.8 and 34.2%). The mean crestal bone loss was 4.7 ± 2.1 mm on the buccal aspect, 0.4 ± 0.5 mm on the mesial aspect, 0.4 ± 0.3 mm on the distal aspect, and 0.3 ± 0.4 mm on the lingual aspect. Conclusion: The findings from this study demonstrated that the placement of implants and Bio‐Oss® particles into fresh extraction sockets resulted in significant buccal bone loss with low osseointegration.     

Clinical and radiographic characteristics of single‐tooth replacements preceded by local ridge augmentation: a prospective randomized clinical trial

Objectives: To assess in a randomized‐clinical trial the influence of three augmentation techniques (chinbone with or without a Bio‐Gide^® membrane and Bio‐Oss^® with a Bio‐Gide^® membrane) on the clinical and radiographic characteristics of hard and soft tissues around implants and adjacent teeth in the reconstructed maxillary anterior region, up to 1 year after functional loading. Materials and methods: Ninety‐three patients requesting single‐tooth replacement and presenting with a horizontal (bucco‐palatinal) bone deficiency were included. After augmentation, 93 ITI‐Esthetic^Plus implants were placed. Clinical variables, standardized photographs and radiographs were analysed to assess the impact on the levels of the marginal gingiva (MGL) and marginal bone (MBL) around implants and adjacent teeth, viz at pre‐augmentation, pre‐implantation (TPI) and 1 (T₁) and 12 (T₁₂) months after final crown placement. Results: Implant survival was 97.8%. No significant differences were observed in the treatment outcomes of the three augmentation modalities. Combining the three modalities, a slight but significant increase in the implants approximal pocket depth was found between T₁ and T₁₂. Approximal bone loss at the implant between T₁ and T₁₂ was 0.14 ± 0.76 mm (mesial) and 0.14 ± 0.47 mm (distal); the approximal MGL slightly increased (mesial: 0.24 ± 0.46 mm, distal: 0.25 ± 0.66 mm), and the buccal MGL decreased (0.11 ± 0.61 mm). Bone loss at the adjacent teeth, although minor, was significant between TPI and T₁. No correlations were observed in changes of MBL and MGL. Conclusions: None of the three applied augmentation technique procedures influenced the characteristics of the MGL and MBL or the implant survival of single‐tooth replacements. Peri‐implant hard and soft tissues were very stable in the first year after loading.     

Efficacy of a bioactive glass–ceramic (Biosilicate®) in the maintenance of alveolar ridges and in osseointegration of titanium implants

Objectives: The aims of this research were to evaluate the efficacy of a bioactive glass–ceramic (Biosilicate^®) and a bioactive glass (Biogran^®) placed in dental sockets in the maintenance of alveolar ridge and in the osseointegration of Ti implants. Material and methods: Six dogs had their low premolars extracted and the sockets were implanted with Biosilicate^®, Biogran^® particles, or left untreated. After the extractions, measurements of width and height on the alveolar ridge were taken. After 12 weeks a new surgery was performed to take the final ridge measurements and to insert bilaterally three Ti implants in biomaterial‐implanted and control sites. Eight weeks post‐Ti implant placement block biopsies were processed for histological and histomorphometric analysis. The percentages of bone–implant contact (BIC), of mineralized bone area between threads (BABT), and of mineralized bone area within the mirror area (BAMA) were determined. Results: The presence of Biosilicate^® or Biogran^® particles preserved alveolar ridge height without affecting its width. No significant differences in terms of BIC, BAMA, and BABT values were detected among Biosilicate^®, Biogran^®, and the non‐implanted group. Conclusions: The results of the present study indicate that filling of sockets with either Biosilicate^® or Biogran^® particles preserves alveolar bone ridge height and allows osseointegration of Ti implants. To cite this article:
Roriz VM, Rosa AL, Peitl O, Zanotto ED, Panzeri H, de Oliveira PT. Efficacy of a bioactive glass–ceramic (Biosilicate^®) in the maintenance of alveolar ridges and in osseointegration of titanium implants.
Clin. Oral Impl. Res. 21 , 2010; 148–155.
doi: 10.1111/j.1600‐0501.2009.01812.x     

Bone regeneration at implants placed into extraction sockets of maxillary incisors in dogs

Aim: To compare the influence of autologous or deproteinized bovine bone mineral as grafting material on healing of buccal dehiscence defects at implants installed immediately into the maxillary second incisor extraction socket in dogs. Material and methods: In the maxillary second incisor sockets of 12 Labrador dogs, implants were installed immediately following tooth extraction. A standardized buccal defect was created and autologous bone particles or deproteinized bovine bone mineral were used to fill the defects. A collagen membrane was placed to cover the graft material, and the flaps were sutured to fully submerge the experimental areas. Six animals were sacrificed after 2 months, and six after 4 months of healing. Ground sections were obtained for histological evaluation. Results: After 2 months of healing, all implants were osseointegrated. All buccal dehiscence defects were completely filled after 2 months irrespective of the augmentation material (autologous bone or Bio‐Oss^®) applied. Bone‐to‐implant contact (BIC) on the denuded implant surfaces was within a normal range of 30–40%. However, the newly formed tissue at 2 months was partially resorbed (>50% of the area measurements) after 4 months. Conclusions: Applying either autologous bone or deproteinized bovine bone mineral to dehiscences at implants installed immediately into extraction sockets resulted in high degree of regeneration of the defects with satisfactory BIC on the denuded implant surface. To cite this article:
De Santis E, Botticelli D, Pantani F, Pereira FP, Beolchini M, Lang NP. Bone regeneration at implants placed into extraction sockets of maxillary incisors in dogs.
Clin. Oral Impl. Res. 22 , 2011; 430–437.     

Histological evaluation of the peri‐implant tissues of three human‐retrieved Straumann implants

The most frequently‐used histological parameters to define dental implant osseointegration include bone‐to‐implant contact and quantitative and qualitative assessments of the surrounding tissue (rate of mineralized/non‐mineralized tissue and proportion of lamellar and woven bone compared to soft tissue or bone marrow). The aim of this paper was to present the histological features of the bone tissue surrounding three well‐functioning Straumann SLA and SLActive implants placed in two patients after 12 and 60 months of loading. The percentage of osseointegration ranged from 66.4% and 71.9% for SLA surfaces, to 88.3% for the SLActive implant. Such results confirm that osseointegration occurs with high rates of bone‐to‐implant contact in humans, and that implants can be similarly clinically successful, although they show different bone‐to‐implant contact values.