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     

Comparison of two resorbable membrane systems in bone regeneration after removal of wisdom teeth: a randomized-controlled clinical pilot study

Objectives: To compare the performance and safety of Inion GTR^? Biodegradable Membrane System and Geistlich resorbable bilayer Bio‐Gide^® membrane in human bone regeneration. Material and methods: In a multicenter, split blind, comparative, randomized, prospective, pilot study 15 patients have been randomized at surgery whether to be treated either with Inion GTR^? Biodegradable Membrane System on one and Geistlich resorbable bilayer Bio‐Gide^® membrane on the other side or vice versa after surgical removal of both fully impacted wisdom teeth. During the follow‐up visits at week 1, 2 and 6 and at months 3 and 6 the general state, the wound, eventual adverse events and the medication of the patients were assessed. Computed Tomography (CT) scans were performed immediately and 3 months after the surgery, before biopsy collection. Semi‐quantitative histological evaluation and histomorphometric analyses were performed according to the ISO 10993‐6 standard. New bone formation and membrane integration were evaluated by CT scan measurements. Tissue healing was evaluated clinically and by photographs between the time on teeth extraction and during follow ups. Results: Five patients were smokers, none drank alcohol. Mild adverse events like wound infection, haematoma or late swelling of the gums occurred in three patients. The trephine bur harvest of bone biopsies under local anaesthesia was uneventful. Whereas specimens from the sites treated with the Inion membrane yielded 17.0% (SD 24%), the Bio‐Gide membrane sites yielded 13.5% (SD 15%) of bone tissue density. In sites treated with the Inion membrane, 9.5% of old bone density and 7.5% of newly formed bone could be found, whereas the Bio‐Gide^® membrane sites showed 3.8% of old bone density and 9.8% of newly formed bone. There were no statistically significant differences between the two groups with respect to the two variables. The osteoid rim was more extended with the Bio‐Gide^® (6.6 mm) than with the Inion membrane (5.1 mm) but the difference between the two treatments did not reach statistical significance. Highly significant reductions in the area of the defect with both membranes were detected with significant increases in CT density at the immediate inferio–buccal adjacent bone and in the surgical defect area with both membranes. However, there was neither significant change in CT density in the immediate inferior–lingual adjacent bone of the two membranes, nor significant difference between the membranes on any of the four measurements (area of defect: P=0.1354; CT density immediate inferio–buccal adjacent bone: P=0.7615; CT density surgical defect area: P=0.1876; CT density immediate inferio–lingual adjacent bone: P=0.4212). Conclusion: The overall clinical outcome was satisfying and the majority of the patients showed an uneventful healing phase. Both membranes presented similar capacities regarding their barrier function and were associated with analogous bone regeneration. No statistically valid evidence about the superiority of one particular membrane was obtained. For the patient the only difference is that one product is animal derived and the other synthetic.     

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.     

The effect of maximum bite force on marginal bone loss of mini‐implants supporting a mandibular overdenture: a randomized controlled trial

Objectives: To evaluate the effect of maximum bite force (mBF) on marginal bone loss (MBL) around mini‐implants in edentulous patients wearing mandibular overdentures with two retention systems: ball and bar. Material and methods: Forty‐five totally edentulous patients were selected from a public health center. All of them received two mini‐implants (1.8 × 15 mm; Sendax^®) in the anterior mandible using a minimally invasive technique. A single randomization was performed to allocate the patients in two groups. Group I (n=22) received two single ball‐type mini‐implants and Group II (n=23) received two mini‐implants splinted with a prefabricated bar. The mBF was recorded using a press‐sensitive sheet Dental Prescale^® (Fuji) and MBL using standardized radiographs of each mini‐implant at the baseline and 5, 7, 10, and 15 months after surgery; the values were compared between groups. Results: Two members of Group I failed to complete the study, decreasing the number of participants to 20. There was no relationship between the mBF and the MBL of the mini‐implants (Spearman's ρr_s=0.147; P=0.378). At the 15‐month follow‐up, the average mBF for Group I (ball) was 247.53 ± 132.91 N and that of Group II (bar) only 203.23 ± 76.85 N (Mann–Whitney test; P=0.586). The MBL values were also higher for Group I (1.40 ± 1.02 mm) than Group II (0.84 ± 0.66 mm) during the entire 15‐month follow‐up period (Mann–Whitney test; P=0.077). Conclusions: No relationship was found between mBF and MBL for patients wearing overdentures retained on mini‐implants using bar or ball attachment systems. To cite this article:
Jofré J, Hamada T, Nishimura M, Klattenhoff C. The effect of maximum bite force on marginal bone loss of mini‐implants supporting a mandibular overdenture: a randomized controlled trial.
Clin. Oral Impl. Res. 21 , 2010; 243–249.
doi: 10.1111/j.1600‐0501.2009.01834.x     

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     

Effect of rhBMP-2 on guided bone regeneration in humans

Abstract: The aim of the present clinical study was to test whether or not the addition of recombinant human bone morphogenetic protein‐2 (rhBMP‐2) to a xenogenic bone substitute mineral (Bio‐Oss^®) will improve guided bone regeneration therapy regarding bone volume, density and maturation. In 11 partially edentulous patients, 34 Brånemark implants were placed at two different sites in the same jaw (five maxillae, six mandibles) requiring lateral ridge augmentation. The bone defects were randomly assigned to test and control treatments: the test and the control defects were both augmented with the xenogenic bone substitute and a resorbable collagen membrane (Bio‐Gide^®). At the test sites, the xenogenic bone substitute mineral was coated with rhBMP‐2 in a lyophilization process. Following implant insertion (baseline), the peri‐implant bone defect height was measured from the implant shoulder to the first implant–bone contact. After an average healing period of 6 months (SD 0.17, range 5.7–6.2), the residual defects were again measured and trephine burs were used to take 22 bone biopsies from the augmented regions. The healing period was uneventful except for one implant site that showed a wound dehiscence, which spontaneously closed after 4 weeks. Later at reentry, all implants were stable. At baseline, the mean defect height was 7.0 mm (SD 2.67, range 3–12 mm) at test and 5.8 mm (SD 1.81, range 3–8 mm) at control sites. At reentry, the mean defect height decreased to 0.2 mm (SD 0.35, range 0–1 mm) at test sites (corresponding to 96% vertical defect fill) and to 0.4 mm (SD 0.66, range 0–2 mm) at the control site (vertical defect fill of 91%). Reduction in defect height from baseline to reentry for both test and control sites was statistically significant (Wilcoxon P<0.01). Histomorphometric analysis showed an average area density of 37% (SD 11.2, range 23–51%) newly formed bone at test sites and 30% (SD 8.9, range 18–43%) at control sites. The fraction of mineralized bone identified as mature lamellar bone amounted to 76% (SD 14.4, range 47.8–94%) at test compared to 56% (SD 18.3, range 31.6–91.4%) at control sites (paired t‐test P<0.05). At BMP‐treated sites 57% (SD 16.2, range 29–81%) and at control sites 30% (SD 22.6, range 0–66%) of the surface of the bone substitute particles were in direct contact with newly formed bone (paired t‐test P<0.05). It is concluded that the combination of the xenogenic bone substitute mineral with rhBMP‐2 can enhance the maturation process of bone regeneration and can increase the graft to bone contact in humans. rhBMP‐2 has the potential to predictably improve and accelerate guided bone regeneration therapy.     

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%.     

Oral implants placed in bone defects treated with Bio‐Oss®, Ostim®‐Paste or PerioGlas: an experimental study in the rabbit tibiae

Objectives: To compare the histological features of bone filled with Bio‐Oss^®, Ostim‐Paste^® or PerioGlas placed in defects in the rabbit tibiae by evaluating bone tissue composition and the integration of titanium implants placed in the grafted bone. Material and methods: Two cylindrical bone defects, about 4 mm in diameter and 6 mm in depth, were created in the tibiae of 10 rabbits. The defects were filled with either Bio‐Oss^®, PerioGlas, Ostim^®‐Paste or left untreated, and covered with a collagen membrane. Six weeks later, one titanium sandblasted and acid‐etched (SLA) implant was inserted at the centre of each previously created defect. The animals were sacrificed after 6 weeks of healing. Results: Implants placed in bone previously grafted with Bio‐Oss^®, PerioGlas or Ostim^®‐Paste obtained a larger extent of osseointegration, although not statistically significant, than implants placed in non‐grafted bone. The three grafting materials seemed to perform in a similar way concerning their contribution towards implant osseointegration. All grafting materials appeared to be osteoconductive, thus leading to the formation of bridges of mineralized bone extending from the cortical plate towards the implants surface through the graft scaffold. Conclusions: Grafting with the above‐mentioned biomaterials did not add any advantage to the osseointegration of titanium SLA implants in a self‐contained defect.     

Peri-implant health around screw-shaped c.p. titanium machined implants in partially edentulous patients with or without ongoing periodontitis

Abstract: The relationship between periodontitis and peri‐implantitis remains a matter of debate. The present study compared, “within” randomly chosen partially edentulous patients (n=84 subjects, 97 jaws), the marginal bone loss around teeth and implants during 5 years (range 3 to 11 years) following the first year of bone remodelling. The patients had all been rehabilitated by means of screw‐shape c.p. titanium implants with a machined surface (Brånemark system^®). During the 5 years observation interval, periodontal parameters (marginal bone and attachment loss, the latter for teeth only) were collected together with data on confounding factors (smoking, oral hygiene, tooth loss). Marginal bone loss was measured through long‐cone intra‐oral radiographs. The mean “interval” bone loss was significantly (P=0.0001) higher around teeth (0.48±0.95 mm) than around implants (0.09±0.28 mm). The corresponding data for the “worst” performing tooth (0.99±1.25 mm) and implant (0.19±0.32 mm) per subject showed the same tendency. Neither attachment nor bone loss around teeth correlated with marginal bone loss around implants. This study indicated that the rate of bone loss around screw‐shape c.p. titanium implants with a machined surface (Brånemark system^® implants) was not influenced by the progression rate of periodontal destruction around the remaining teeth within the same jaw.     

Graft‐Free Maxillary Sinus Floor Elevation: A Systematic Review and Meta‐Analysis

Background: This systematic review and meta‐analysis aims to investigate survival rates of dental implants placed simultaneously with graft‐free maxillary sinus floor elevation (GFSFE). Factors influencing amount of vertical bone gain (VBG), protruded implant length (PIL) in sinus at follow‐up (PILf), and peri‐implant marginal bone loss (MBL) are also evaluated. Methods: Electronic and manual searches for human clinical studies on simultaneous implant placement and GFSFE using the lateral window or transcrestal approach, published in the English language from January 1976 to March 2016, were conducted. The random‐effects model and mixed‐effect meta‐regression were used to analyze weighted mean values of clinical parameters and evaluate factors that influenced amount of VBG. Results: Of 740 studies, 22 clinical studies were included in this systematic review. A total of 864 implants were placed simultaneously with GFSFE at edentulous sites having mean residual bone height of 5.7 ± 1.7 mm. Mean implant survival rate (ISR) was 97.9% ± 0.02% (range: 93.5% to 100%). Weighted mean MBL was 0.91 ± 0.11 mm, and it was significantly associated with the postoperative follow‐up period (r = 0.02; R² = 43.75%). Weighted mean VBG was 3.8 ± 0.34 mm, and this parameter was affected significantly by surgical approach, implant length, and PIL immediately after surgery (PILi) (r = 2.82, 0.57, 0.80; R² = 19.10%, 39.27%, 83.92%, respectively). Weighted mean PILf was 1.26 ± 0.33 mm (range: 0.3 to 2.1 mm). Conclusion: Within limitations of the present systematic review, GFSFE with simultaneous implant placement can achieve satisfactory mean ISR of 97.9% ± 0.02%.     

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     

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.     

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

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

Platelet‐rich fibrin membranes as scaffolds for periosteal tissue engineering

Objectives: Platelet‐rich fibrin (PRF)‐based membranes have been used for covering alveolar ridge augmentation side in several in vivo studies. Few in vitro studies on PRF and no studies using human periosteal cells for tissue engineering have been published. The aim is a comparison of PRF with the commonly used collagen membrane Bio‐Gide^® as scaffolds for periosteal tissue engineering. Material and methods: Human periosteal cells were seeded on membrane pieces (collagen [Bio‐Gide^®] and PRF) at a density of 10⁴ cells/well. Cell vitality was assessed by fluorescein diacetate (FDA) and propidium iodide (PI) staining, biocompatibility with the lactate dehydrogenase (LDH) test and proliferation level with the MTT, WST and BrdU tests and scanning electron microscopy (SEM). Results: PRF membranes showed slightly inferior biocompatibility, as shown by the LDH test. The metabolic activity measured by the MTT and WST tests was higher for PRF than for collagen (BioGide^®). The proliferation level as measured by the BrdU test (quantitative) and SEM examinations (qualitative) revealed higher values for PRF. Conclusion: PRF appears to be superior to collagen (Bio‐Gide^®) as a scaffold for human periosteal cell proliferation. PRF membranes are suitable for in vitro cultivation of periosteal cells for bone tissue engineering. To cite this article:
Gassling V, Douglas T, Warnke, PH, Açil Y, Wiltfang J, Becker ST. Platelet‐rich fibrin membranes as scaffolds for periosteal tissue engineering.
Clin. Oral Impl. Res. 21 , 2010; 543–549.
doi: 10.1111/j.1600‐0501.2009.01900.x     

Randomized Controlled Trial to Compare Two Bone Substitutes in the Treatment of Bony Dehiscences

Aim: This in vivo split‐mouth randomized controlled trial compared a synthetic bone substitute with a bovine bone mineral to cover bone dehiscences after implant insertion. Materials and Methods: Fourteen patients received four to six implants to support an overdenture. Two comparable dehiscences within the same patient were first covered with a layer of autogenous bone, followed by a layer of either Bio‐Oss® (group 1; Geistlich Pharma AG, Wolhusen, Switzerland) or Straumann BoneCeramic® (group 2; Institut Straumann AG, Basel, Switzerland) and sealed by a resorbable membrane. The change in vertical dimension of the defect was measured at implant placement and at abutment connection (6.5 months). Clinical and radiological parameters were evaluated up to 1 year of loading. Results: The vertical size of the defect at surgery was 6.4 ± 1.6 mm for group 1 and 6.4 ± 2.2 mm for group 2 sites, measured from the implant shoulder. After 6.5 months, the depth of the defect was reduced to 1.5 ± 1.2 mm and 1.9 ± 1.2 mm for group 1 and group 2 sites, respectively (p > 0.05). No implants failed during follow‐up. Mean marginal bone loss over the SLActive surface was 0.94 mm (group 1), 0.81 mm (group 2), and 0.93 mm (group 3, no dehiscence) after 1 year of loading. Conclusion: Both bone substitutes behaved equally effectively.     

Evaluation of 316 narrow diameter implants followed for 5–10 years: a clinical and radiographic retrospective study

Objectives: Narrow diameter implants (NDIs; diameter >3.75 mm) are useful in replacement of missing incisor teeth and when the bucco‐lingual width of the edentulous crest is insufficient. The present study evaluated the success and survival rates, peri‐implant parameters, mechanical and prosthetic post‐loading complications of NDIs followed over a 10‐year period. Material and methods: Three hundred and sixteen NDIs were inserted into 139 patients and restored with 120 prostheses. Clinical and radiographic assessment data were collected during recall visits. Implant success (SC), cumulative survival rate (CSR), marginal bone loss (MBL), peri‐implant conditions and prosthetic complications were assessed. Cox proportional hazards regression analysis, Kaplan–Meier survival curves with the log‐rank test and life table analysis were used to evaluate the outcome of NDIs within comparable subgroups. MBL and peri‐implant parameters measured annually were further analyzed. Results: The mean follow‐up time was 9.1 years (range: 60–124 months). Twelve implants were lost in the healing phase and two during function. The mean MBL in the maxilla and the mandible was 1.32 ± 0.13 and 1.28 ± 0.3 mm, respectively, after 10 years. SC and CSR were 91.4% and 92.3%, respectively, after 124 months. Smoking and posterior localization were associated with an increased risk of failure. Cement loosening (16.8%) was the most common prosthetic complication. No implants were fractured. Conclusions: NDIs can be used with confidence where a regular diameter implant is not suitable. MBL around NDIs occurred predominantly within 2 years of loading and was minimal thereafter. Further studies are required to clarify the possible risks associated with smoking and posterior placement. To cite this article:
Arιsan V, Bolukbasι N, Ersanlι S, Ozdemir T. Evaluation of 316 narrow diameter implants followed for 5–10 years: a clinical and radiographic retrospective study.
Clin. Oral Impl. Res. 21 , 2010; 296–307.
doi: 10.1111/j.1600‐0501.2009.01840.x     

Marginal Bone Loss in Implants Placed in the Maxillary Sinus Grafted With Anorganic Bovine Bone: A Prospective Clinical and Radiographic Study

Background: Sinus elevation is a reliable and often‐used technique. Success of implants placed in such situations, even with bone substitutes alone, prompted the authors of this study to strive for bone loss close to zero and research variables that cause higher or lower rates of resorption. The objective of this study is to evaluate survival rates and marginal bone loss (MBL) around implants placed in sites treated with maxillary sinus augmentation using anorganic bovine bone (ABB), and identify surgical and prosthetic prognostic variables. Methods: Fifty‐five implants were placed in 30 grafted maxillary sinuses in 24 patients. Periapical radiographs were evaluated immediately after implant placement (baseline), 6 months, and at the most recent follow‐up. MBL was calculated from the difference between initial and final measurements, taking into account a distortion rate for each radiograph compared with original implant measurements. Results: Survival rate was 98.2%, with only one implant lost (100% survival rate after loading) over a mean follow‐up time of 2.0 ± 0.9 years. MBL ranged from 0 to 2.85 mm: 75.9% of mesial sites and 83.4% of distal sites showed <1 mm of MBL, whereas 35.2% of mesial sites and 37% of distal sites exhibited no bone loss. MBL was significantly (P <0.05) greater in open‐flap compared with flapless surgery. Conclusions: Within the limitations of the present study, it was concluded that maxillary sinus elevation with 100% ABB gives predictable results, and that flapless surgery results in less MBL compared with traditional open‐flap surgery.     

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.     

Peri-implant tissue response to TiO2 surface modified implants

Objectives: The objective of this study was to evaluate peri‐implant soft tissue attachment and alveolar bone height on nanoporous TiO₂ thin film on commercial titanium dental implants compared with unmodified standard implants. Material and methods: In six adult beagle dogs, the mandibular premolars P2–P4 were extracted bilaterally. Sol–gel‐derived nanoporous TiO₂ thin film was produced on smooth coronal part of standard ITI^® Straumann implants (4.1 mm × 8.0 mm) by dip coating method. After 3 months healing period of the extraction sockets modified (n=24) and unmodified (n=11) control implants were placed bilaterally. The animals were killed after 8 weeks and the samples were retrieved and processed for histologic/histomorfometric and TEM/SEM evaluations. Results: Histological examination showed mild or absent inflammatory reaction in peri‐implant connective tissues around the surface modified implants. Further, junctional epithelium (JE)/connective tissue (CT) appeared to be in immediate contact with the experimental implants. Of the experimental implants, 22% were judged to be detached from the implant surface while 45% of the untreated control implants were detached. Dense plaques of hemidesmosomes were found in TEM evaluation of the JE cell membrane facing the surface‐treated implants. In the histomorfometric analysis, the distance between the implant margin and alveolar bone crest was significantly shorter in surface‐treated implants than in the control implants (P<0.02). Conclusion: Nanoporous sol–gel‐derived TiO₂ thin film on ITI^® Straumann dental implants improved soft tissue attachment in vivo.     

Implant treatment in combination with lateral augmentation of the alveolar process: a 3-year prospective study

Background: In patients in whom the height of the alveolar process is adequate but the crest is too narrow to host an implant, lateral augmentation is required. Such augmentations have mostly been performed using autogenous bone blocks secured to the buccal surface. An alternative to autogenous bone may be bovine hydroxyapatite (Bio‐Oss, Geistlich Pharma AG, Wolhusen, Switzerland) or other bone substitutes. Purpose: The aim of this study was to evaluate the clinical and radiographic outcome of dental implants inserted after lateral augmentation of too narrow alveolar processes with a combination of bovine hydroxyapatite (Bio‐Oss) and autogenous bone. Methods: Thirty patients (14 males and 16 females) with a mean age of 41.6 years fulfilled the inclusion criteria. Twenty‐nine augmentation sites with a total of 74 implants could be followed for 3 years. Results: Three implants were lost; these were lost before loading (at the abutment operation). The survival rate was 95.9%. The mean marginal bone loss during the 3‐year observation period was 0.3 ± 0.2 mm. Conclusions: A 50/50 combination of Bio‐Oss and autogenous bone chips stabilized with Tisseel (Baxter AG/Duo Quick AG, Vienna, Austria) was useful for lateral augmentation of the alveolar crest. Lateral grafts with Bio‐Oss, autogenous bone, and Tisseel made it possible to achieve good implant stability and high implant survival results. The bone level changes adjacent to the implants were the same as in nongrafted cases.