Implant survival after sinus elevation with Straumann(®) BoneCeramic in clinical practice: ad-interim results of a prospective study at a 15-month follow-up

Objectives: Elevation of the sinus floor with Straumann^® BoneCeramic gave promising results in some recent clinical studies. However, no study has evaluated the long‐term survival of implants after this surgical procedure. We are conducting a prospective, observational study to evaluate the long‐term implant survival after this surgical procedure in clinical practice. We present here an ad‐interim report of this study, including only patients with ≥12‐month follow‐up after implant placement. Methods: This prospective cohort study will last until a follow‐up of 5 years will be achieved in at least 50 patients. Inclusion criteria are: age ≥18 years; presence of a maxillary partial unilateral or bilateral edentulism involving the premolar/molar areas; elective rehabilitation with oral implants; and physical capability to tolerate conventional surgical and restorative procedures. Patients are treated according to the two‐stage technique and the preparation is filled with Straumann^® BoneCeramic. Implant survival is evaluated every 3 months for the first 2 years, and then every 6 months up to 5 years. Results: Fifteen patients are considered in this ad‐interim analysis. Mean follow‐up was 14.9 ± 3.1 (range: 6–18 months). In total, three implants failed, in one single patient, 6 months after insertion. The cumulative implant survival rate was 92.5% (95% confidence interval: 83.0–100%). Conclusions: This ad‐interim analysis suggests that the elevation of the sinus floor with Straumann^® BoneCeramic may be an effective clinical option over >1‐year follow‐up. A longer term follow‐up will allow a deeper characterization of these preliminary findings To cite this article:
Covani U, Orlando B, Giacomelli L, Cornelini R, Barone A.
Implant survival after sinus elevation with Straumann^® BoneCeramic in clinical practice: ad‐interim results of a prospective study at a 15‐month follow‐up.
Clin. Oral Impl. Res. 22 , 2011; 481–484
doi: 10.1111/j.1600‐0501.2010.02042.x     

An animal model for sinus floor elevation with great elevation heights. Macroscopic,microscopic, radiological and micro‐CT analysis: ex vivo

Objectives: Different animal models are used for research and training concerning sinus floor elevation. However, there is little information regarding an animal model for elevation heights of approximately 10 mm. The aim of this study was to explore the anatomical aspects of the maxillary sinus of adult pigs and to investigate the suitability of this animal as a model for sinus floor elevation training and research with great elevation heights. Material and methods: Thirty‐four bisected heads of adult domestic pigs were examined 6 h postmortem. Direct sinus floor elevation was performed with an elevation height of 10 mm. Localization, diameters, volume and septa of the maxillary sinus were recorded on lateral X‐rays and macroscopically. The thickness and structure of the maxillary sinus were investigated microscopically. The osseous microstructure of the lateral sinus wall was assessed microscopically and via micro‐CT. Results: The maxillary sinus of the adult pig exhibits an average length of 51±6.2 mm, a height of 31±4.1 mm, a width of 19±1.6 mm and a volume of 31±7.6 cm³. At least one septum could be observed on the floor of each sinus. The mucosal thickness amounted to a mean of 1692±138 μm, and the lateral bony wall of the sinus to a mean of 3±0.3 mm. A laceration of the Schneiderian membrane occurred in 25% during the elevation process. Conclusion: The maxillary sinus of adult domestic pigs is a suitable model for sinus floor elevation training and research with greater elevation heights of up to 10 mm. To cite this article:
Stelzle F, Benner K‐U. An animal model for sinus floor elevation with great elevation heights. Macroscopic, microscopic, radiological and micro‐CT analysis: ex vivo.
Clin. Oral Impl. Res. 21 , 2010; 1370–1378.
doi: 10.1111/j.1600‐0501.2010.01958.x     

Back‐scattered electron imaging and elemental analysis of retrieved bone tissue following sinus augmentation with deproteinized bovine bone or biphasic calcium phosphate

Objectives: To compare resorption of a synthetic biphasic calcium phosphate (BCP) bone–graft substitute with deproteinized bovine bone (DBB) used for human maxillary sinus augmentation. Materials and methods: Eleven patients underwent bilateral maxillary sinus floor augmentation with DBB in one side and a BCP (40%β‐tricalcium phosphate (β‐TCP) and 60% hydroxyapatite) in the contralateral side. Simultaneously, with the augmentation on each side a microimplant was placed vertically from the top of the alveolar crest penetrating the residual bone and the grafting material. Eight months after initial surgery the microimplants were retrieved with a surrounding bone core. The composition of residual graft material and surrounding bone was analysed by scanning electron microscopy and energy dispersive X‐ray spectroscopy. Results: Residual graft material of both types was present as 10–500 μm particles in direct contact with, or completely surrounded by, newly formed bone; smaller particles were also present in non‐mineralized tissue. In the case of BCP the bone–graft substitute interface showed evidence of superficial disintegration of particles into individual grains. Median Ca/P ratios (at.%), determined from >200 discreet sites within residual graft particles and adjacent bone, were: DBB: 1.61 (confidence interval [CI] 1.59–1.64); BCP: 1.5 (CI 1.45–1.52); DBB‐augmented bone: 1.62 (CI 1.59–1.66); BCP‐augmented bone: 1.52 (CI 1.47–1.55); P=0.028 for DBB vs. BCP and DBB‐ vs. BCP‐augmented bone. The reduction in Ca/P ratio for BCP over the healing period is consistent with the dissolution of β‐TCP and reprecipitation on the surface of calcium‐deficient hydroxyapatite. Conclusion: The β‐TCP component of BCP may be gradually substituted by calcium‐deficient hydroxyapatite over the healing period. This process and superficial degranulation of BCP particles may influence the progress of resorption and healing. To cite this article:
Lindgren C, Hallman M, Sennerby L, Sammons R. Back‐scattered electron imaging and elemental analysis of retrieved bone tissue following sinus augmentation with deproteinized bovine bone or biphasic calcium phosphate.
Clin. Oral Impl. Res. 21 , 2010; 924–930.
doi: 10.1111/j.1600‐0501.2010.01933.x     

Flapless, CBCT-guided osteotome sinus floor elevation with simultaneous implant installation. I: radiographic examination and surgical technique. A prospective 1-year follow-up

Background: Survival rates of implants placed in transalveolar sinus floor augmentation sites are comparable with those placed in non‐augmented sites. Flapless implant surgery can minimize postoperative morbidity, alveolar bone resorption and crestal bone loss. The use of cone beam computerized tomography (CBCT) provides 3D presentations with reduced dose exposure. Objectives: To evaluate a flapless, CBCT‐guided transalveolar sinus floor elevation technique with simultaneous implant installation. Material and methods: Fourteen consecutive patients in need of maxillary sinus floor augmentation were enrolled in this study. Preoperative CBCT with a titanium screwpost as an indicator at the intended implant position was used to visually guide the flapless surgical procedure. Twenty one implants all with a length of 10 mm and a diameter of 4.1 and 4.8 mm were inserted and followed clinically and with CBCT for 3, 6 and 12 months postoperatively. Intraoral radiographs were taken for comparison. All patients were provided with permanent prosthetic constructions 8–12 weeks after implant surgery. Results: Ten (47.6%) implants were inserted in residual bone of 2.6–4.9 mm and 11 (52.3%) implants were inserted in residual bone of 5–8.9 mm. No implants were lost after surgery and follow‐up. There was no marginal bone loss during the follow‐up verified by CBCT. The implants penetrated on average 4.4 mm (SD 2.1 mm) into the sinus cavity and the mean bone gain was 3 mm (SD 2.1 mm). Conclusion: Flapless transalveolar sinus lift procedures visually guided by preoperative CBCT can successfully be used to enable placement, successful healing and loading of one to three implants in residual bone height of 2.6–8.9 mm. There was no marginal bone loss during the 3–12 months follow‐up. To cite this article :
Fornell J, Johansson L‐Å, Bolin A, Isaksson S, Sennerby L. Flapless, CBCT‐guided osteotome sinus floor elevation with simultaneous implant installation. I: radiographic examination and surgical technique. A prospective 1‐year follow‐up.
Clin. Oral Impl. Res. 23 , 2012; 28–34.
doi: 10.1111/j.1600‐0501.2010.02151.x     

Early healing after elevation of the maxillary sinus floor applying a lateral access: a histological study in monkeys

Aim: To describe the early healing within the void obtained after the elevation of the sinus mucosa and simultaneous implant installation without the use of any grafting material in monkeys. Material and methods: Implants were installed simultaneously with the elevation of the maxillary sinus using the lateral approach in eight monkeys without the use of grafting material. The healing after 4, 10, 20 and 30 days was evaluated in the area distal to the implants. Paraffin sections were prepared and analyzed using qualitative histological methods. Results: The healing process was initiated by the formation of a coagulum and followed by a provisional matrix and woven bone. Subsequently, a parallel‐fiber bone replaced woven bone. The dimension of the elevated area shrank during the healing process. Sprouts of woven bone, present to a moderate extent after 4 days, were more numerous after 10 and 20 days. Newly formed bone originated from the sinus walls and septa, while there was no evidence of participation of the Schneiderian membrane in this process. After 30 days, the window access appeared to be closed by a layer of newly formed trabecular bone. Conclusions: The coagulum that filled the void distal to the implant after simultaneous elevation of the sinus floor gave rise to newly formed bone. However, the void occupied by the coagulum shrank substantially. The Schneiderian membrane did not provide a basis for new bone formation in the early phase of healing. To cite this article:
Scala A, Botticelli D, Rangel IG Jr, de Oliveira JA, Okamoto R, Lang NP. Early healing after elevation of the maxillary sinus floor applying a lateral access: a histological study in monkeys.
Clin. Oral Impl. Res. 21 , 2010; 1320–1326.
doi: 10.1111/j.1600‐0501.2009.01964.x     

The use of autologous venous blood for maxillary sinus floor augmentation in conjunction with sinus membrane elevation: an experimental study

Background: There have been reports of successful bone formation with sinus floor elevation induced by simply elevating the maxillary sinus membrane and filling the sinus cavity with a blood clot. Purpose: We investigated the feasibility of maxillary sinus floor augmentation using the patient's own venous blood in conjunction with a sinus membrane elevation procedure. Materials and methods: An implant that protruded 8 mm into the maxillary sinus after sinus membrane elevation was placed in the maxillary sinus of six adult female mongrel dogs. The resulting space between the membrane and the sinus floor was filled with autologous venous blood retrieved from each dog. The implants were left in place for 6 months. Results: During the experimental period, the created space collapsed and the sinus membrane fell down onto the implant. A small amount of new bone formation occurred in the space created by the collapsed membrane. The average height of newly formed bone around the implants in the sinus was 2.7±0.7 mm on the buccal side and 0.6±0.3 mm on the palatal side. Conclusion: The results of this pilot study indicate that blood clots do not have sufficient integrity to enable the sinus membrane to remain in an elevated position for therapeutically effective periods of time. Accordingly, it is recommended that this method be used only when a small aount of new bone formation is necessary around implants in the maxillary sinus cavity. To cite this article:
Kim H‐R, Choi B‐H, Xuan F, Jeong S‐M. The use of autologous venous blood for maxillary sinus floor augmentation in conjunction with sinus membrane elevation: an experimental study.
Clin. Oral Impl. Res. 21 , 2010; 346–349.
doi: 10.1111/j.1600‐0501.2009.01855.x     

Maxillary sinus floor elevation with bovine bone mineral combined with either autogenous bone or autogenous stem cells: a prospective randomized clinical trial

Aim: To assess whether differences occur in bone formation after maxillary sinus floor elevation surgery with bovine bone mineral (BioOss^®) mixed with autogenous bone or autogenous stem cells. The primary endpoint was the percentage of new bone three months after the elevation procedure. Material and methods: In a randomized, controlled split‐mouth design, in 12 consecutive patients (age 60.8 ± 5.9 years, range 48–69 years) needing reconstruction of their atrophic maxilla, a bilateral sinus floor augmentation procedure was performed. Randomly, on one side the augmentation procedure was performed with bovine bone mineral (BioOss^®) seeded with mononuclear stem cells harvested from the posterior iliac crest (test group) while BioOss^® mixed with autogenous bone (harvested from the retromolar area) was applied on the contra‐lateral side (control group). On 14.8 ± 0.7 weeks after the sinus floor elevation, biopsies from the reconstructed areas were taken at the spots where subsequently the endosseous implants were placed. The biopsies were histomorphometrically analyzed. Results: Significantly more bone formation was observed in the test group (17.7 ± 7.3%) when compared with the control group (12.0%± 6.6; P=0.026). In both the test and control group, all implants could be placed with primary stability. In one patient, not all biopsies contained BioOss^®. This patient was excluded from analysis. Conclusion: Mesenchymal stem cells seeded on BioOss^® particles can induce the formation of a sufficient volume of new bone to enable the reliable placement of implants within a time frame comparable with that of applying either solely autogenous bone or a mixture of autogenous bone and BioOss^®. This technique could be an alternative to using autografts. To cite this article: Rickert D, Sauerbier S, Nagursky H, Menne D, Vissink A, Raghoebar GM. Maxillary sinus floor elevation with bovine bone mineral combined with either autogenous bone or autogenous stem cells: a prospective randomized clinical trial.
Clin. Oral Impl. Res. 22 , 2011; 251–258.
doi: 10.1111/j.1600‐0501.2010.01981.x     

Osteotome sinus floor elevation with or without grafting: a preliminary clinical trial

Objectives: This clinical trial aimed (1) to evaluate the predictability of the osteotome sinus floor elevation (OSFE) technique, (2) to study the influence of simultaneous grafting on the clinical success of placing dental implants in the posterior maxilla using OSFE and (3) to observe the bone changes in the elevated space with OSFE without grafting. Material and methods: Two hundred and eighty Straumann^® implants were placed in the posterior maxillae of 202 patients using OSFE. One hundred and ninety‐one implants were placed in 125 patients without grafting. The implants were allowed to heal for 3–4 months for non‐grafted implants and for 6–8 months for grafted cases. For radiographic analyses, periapical and panoramic radiographs were taken of 30 implants at 3 and 9 months to assess the bone changes for the elevated sites without grafting. Results: Two hundred and sixty‐eight of 280 implants fulfilling the survival criteria represented a cumulative survival rate of 95.71%. The residual bone height (RBH) was 5.6±2.5 mm for the non‐grafted group and 4.7±2.1 mm for the grafted group. The perforation rate was 4.29%. No significant differences were found between the two groups in RBH, survival rate or membrane perforation rate. The radiographic analyses demonstrated that new bone formation in the elevated sinus was visible and the endo‐sinus bone gain was 2.26±0.92 mm and 2.66±0.87 mm at 3‐ and 9‐ month follow‐up, respectively. Crestal bone loss (CBL) was 0.89±0.5 and 1.2±0.48 mm at 3 and 9 months. For the two test groups, RBH did not have a significant influence on the survival of the implants. At the 9‐month follow‐up, the endo‐sinus bone gain and CBL were not significantly correlated to RBH. The implant protrusion length was significantly correlated to the endo‐sinus bone gain. Conclusions: The findings of this study indicated that uneventful osseointegration may be predictable on applying OSFE whether with or without grafting in atrophic posterior maxilla. Spontaneous new bone formation seemed to be expected with implants placed using OSFE without simultaneous grafting. To cite this article:
Lai H‐C, Zhuang L‐F, Lv X‐F, Zhang Z‐Y, Zhang Y‐X, Zhang Z‐Y. Osteotome sinus floor elevation with or without grafting: a preliminary clinical trial.
Clin. Oral Impl. Res. 21 , 2010; 520–526.
doi: 10.1111/j.1600‐0501.2009.01889.x     

Anatomic and histological analysis in a goat model used for maxillary sinus floor augmentation with simultaneous implant placement

Objectives: The aim of the present study was to carry out an anatomic survey on the goat maxillary sinus in order to provide accurate and definite anatomic parameters for the design of sinus floor elevation and dental implantation studies in this valuable preclinic animal model. Material and methods: The anatomic topographic structure of the maxillary sinuses was studied bilaterally in 10 adult goats by a gross survey as well as a histological analysis with parasagittal or coronal sections. Then following parameters were defined and measured: (1) maxillary alveolar height (MAH): vertical height from the alveolar crest to the sinus floor; (2) sinus lateral floor width (SLFW): horizontal distance from the lateral border of the anteroposterior bone crest to the sinus lateral wall; (3) infraorbital canal diameter (ICD); and (4) maxillary sinus volume (MSV): the volume occupied by water injected into the sinus. The data were presented with mean±SD on both sides. Results: The goat has a maxillary sinus similar to humans, with a slender pyramidal shape that pneumatizes the entire maxilla, and a sinus wall covered with a mucosal lining. From the maxillary sinus floor, there is an anteroposterior bone crest protruding with the infraorbital canal enveloped. It divides the maxillary sinus floor into two parts. The SLFW of the lateral part of the maxillary sinus floor becomes broader, about 5.905±1.475 mm in the third premolar site, and the MAH increases towards the posterior area, where the maxillary sinus floor is close to the related teeth roots. According to original metrical data, we also proposed a possible operation procedure for sinus floor augmentation. Conclusions: There is enough space in the lateral floor of the maxillary sinus for dental implantation, and the third premolar area might be a suitable position suggested for maxillary sinus augmentation with simultaneous implant placement in a goat model. To cite this article:
Zou D, Guo L, Lu J, Zhang X, Zhang Z, Jiang X. Anatomic and histological analysis in a goat model used for maxillary sinus floor augmentation with simultaneous implant placement.
Clin. Oral Impl. Res. 21 , 2010; 65–70.     

Reamer-mediated transalveolar sinus floor elevation without osteotome and simultaneous implant placement in the maxillary molar area: clinical outcomes of 391 implants in 380 patients

Objectives: Minimally invasive sinus elevation and augmentation using a transalveolar approach can reduce perioperative complications and patient discomfort. A specially designed reamer accomplishes this without the use of an osteotome or a mallet. The objective of this study is to present this technique with relevant clinical cases and patient outcomes. Material and methods: Series of reamers with one cutting and one reaming edge were used to prepare an osteotomy site for posterior maxillary areas. A total of 391 osteotomies were prepared with the reamer in 380 patients, and 373 implants were placed simultaneously. In addition to the procedure's success parameters, levels of intraoperative patient comfort were monitored using a visual analogue scale. Results: The mean height of the residual alveolar process was 5.8 (0.9) mm, whereas mean elevation of the sinus floor was 6.2 (0.4) mm. Eighteen (4.6%) Schneiderian membrane perforations occurred, and the 2‐year survival rate was 95.4%. The success rate was 92.7% in sites with thin sinus floors (<4 mm) and 96.4% in sites with greater bone height (>4 mm). None of the patients experienced any discomfort during the procedure. Conclusions: Within the limits of the present study, it can be concluded that reamer‐mediated transalveolar sinus floor elevation is a reliable method for implant placement in the posterior maxilla, even at sites with ≤4 mm of residual alveolar bone height. This reamer‐mediated procedure is less invasive than traditional osteotomy and can minimize patient discomfort during sinus floor elevation. To cite this article :
Ahn S‐H, Park E‐J, Kim E‐S. Reamer‐mediated transalveolar sinus floor elevation without osteotome and simultaneous implant placement in the maxillary molar area: clinical outcomes of 391 implants in 380 patients.
Clin. Oral Impl. Res. 23 , 2012; 866–872.
doi: 10.1111/j.1600‐0501.2011.02216.x     

Lack of influence of the Schneiderian membrane in forming new bone apical to implants simultaneously installed with sinus floor elevation: an experimental study in monkeys

Aim: To describe the early healing processes around the implants installed after elevation of the sinus mucosa applying the lateral access technique without the use of grafting material. Material and methods: Immediately after the elevation of the maxillary sinus Schneiderian membrane by the lateral approach in eight monkeys, implants were installed without the use of grafting material. The healing of the tissue around the implants was evaluated after 4, 10, 20 and 30 days. Ground sections were prepared and analyzed histologically. Results: After 4 days of healing, the formation of coagulum and provisional matrix was documented within the elevated area. At 10‐day interval, sprouts of woven bone were in continuity with the parent bone, and partly in contact with the implant surface at the base of the augmented area. While bone‐to‐implant contact increased after 20 and 30 days, the area underneath the Schneiderian membrane appeared reduced in volume and condensed toward the apex of the implants. The sinus mucosa was to some extent collapsed onto the implant surface and on the newly formed bone. Conclusions: The void initially occupied by the coagulum after sinus membrane elevation shrank substantially during the observation period. A lack of influence of the Schneiderian membrane in bone formation apical to implants was documented in the early phase of healing. To cite this article:
Scala A, Botticelli D, Faeda RS, Rangel IG Jr, de Oliveira, JA, Lang NP. Lack of influence of the Schneiderian membrane in forming new bone apical to implants simultaneously installed with sinus floor elevation: an experimental study in monkeys.
Clin. Oral Impl. Res. 23 , 2012; 175–181.
doi: 10.1111/j.1600‐0501.2011.02227.x     

Maxillary sinus floor elevation and grafting with deproteinized bovine bone mineral: a clinical and histomorphometric study

Objectives: This study evaluated the histomorphometric and clinical outcomes of maxillary sinus floor elevation using deproteinized bovine bone mineral (DBBM). Material and methods: Maxillary sinuses with a residual vertical height of <5 mm were augmented with DBBM alone before implant placement 9 months later. At the time of implant surgery, trephine samples were removed and histological and histomorphometric analyses were performed to examine the percentage of bone and residual graft using point counting and software‐aided analysis. Patients were recalled for clinical and radiographic examination up to 3 years later. Results: Twenty‐five patient specimens were analysed. The percentages of regenerated bone and residual graft material were 19% and 40%, respectively. Software‐aided analysis was comparable to point counting. Twelve patients attended for clinical follow‐up. Implants placed into this regenerated bone exhibited success and survival rates of 100% after an average follow‐up of 3 years. The average vertical height gained was 7.9 mm. Conclusions: The use of DBBM alone in maxillary sinus floor elevation is a predictable method to gain vertical bone height in the posterior maxilla. To cite this article :
Lee DZ, Chen ST, Darby IB. Maxillary sinus floor elevation and grafting with deproteinized bovine bone mineral: a clinical and histomorphometric study.
Clin. Oral Impl. Res. 23 , 2012; 918–924
doi: 10.1111/j.1600‐0501.2011.02239.x     

Use of a titanium device in lateral sinus floor elevation: an experimental study in monkeys

Aim: To evaluate the effect of a space‐maintaining device fixed to the lateral wall of the maxillary sinus after the elevation of the sinus mucosa on bone filling of the sinus cavity. Material and methods: Immediately after the elevation of the maxillary sinus Schneiderian membrane accomplished through lateral antrostomy in four monkeys, a titanium device was affixed to the lateral sinus wall protruding into the sinus cavity to maintain the mucosa elevated without the use of grafting material. The healing of the tissue around the implants was evaluated after 3 and 6 months. Ground sections were prepared and analyzed histologically. Results: The void under the elevated sinus membrane, originally filled with the blood clot, was reduced after 3 as well as after 6 months of healing of about 56% and 40.5%, respectively. In seven out of eight cases, the devices had perforated the sinus mucosa. The formation of mineralized bone and bone marrow amounted to about 42% and 69% after 3 and 6 months, respectively. The connective tissue represented about 53% and 23% of the newly formed tissue after 3 and 6 months, respectively. Conclusions: New bone formation was found below the devices. However, shrinkage of the newly formed tissue was observed both after 3 and 6 months of healing. Hence, the space‐maintaining function of the devices used in the present study has to be questioned. To cite this article:
Schweikert M, Botticelli D, de Oliveira JA, Scala A, Salata LA, Lang NP. Use of a titanium device in lateral sinus floor elevation: an experimental study in monkeys.
Clin. Oral Impl. Res. 23 , 2012; 100–105.
doi: 10.1111/j.1600‐0501.2011.02200.x     

Maxillary sinus augmentation with microstructured tricalcium phosphate ceramic in sheep

Objective: The objective of this study was to evaluate the biological performance of osteoinductive microstructured tricalcium phosphate (MSTCP) particles in maxillary sinus floor augmentation surgery in sheep. Material and methods: Sinus floor augmentation was performed in eight Swifter sheep. In each animal, the maxillary sinus floor was unilaterally augmented with MSTCP particles. Computed tomography (CT) imaging and histological analyses were performed after 12 weeks of implantation. Results: Maxillofacial CT, histology, histomorphometrical analysis and sequential polychrome fluorescent labeling indicated that MSTCP particles provided a scaffold for cell ingrowth and bone formation. After a 12‐week implantation period, the sinuses grafted with MSTCP showed an increased bone height of 6 mm and a mean total bone volume of 43%, with significant degradation of MSTCP particles. Conclusion: MSTCP particles represent a suitable bone substitute material for maxillary sinus floor augmentation surgery. To cite this article:
Klijn RJ, Hoekstra JWM, Van Den Beucken JJJP, Meijer GJ, Jansen JA. Maxillary sinus augmentation with microstructured tricalcium phosphate ceramic in sheep.
Clin. Oral Impl. Res. 23 , 2012; 274–280.
doi: 10.1111/j.1600‐0501.2011.02190.x     

Maxillary sinus grafting with Bio-Oss or Straumann Bone Ceramic: histomorphometric results from a randomized controlled multicenter clinical trial

Introduction: This investigation was designed to compare the histomorphometric results from sinus floor augmentation with anorganic bovine bone (ABB) and a new biphasic calcium phosphate, Straumann^® Bone Ceramic (BCP). Materials and methods: Forty‐eight maxillary sinuses were treated in 37 patients. Residual bone width was ≥6 mm and height was ≥3 mm and <8 mm. Lateral sinus augmentation was used, with grafting using either ABB (control group; 23 sinuses) or BCP (test group; 25 sinuses); sites were randomly assigned to the control or test groups. After 180–240 days of healing, implant sites were created and biopsies taken for histological and histomorphometric analyses. The parameters assessed were (1) area fraction of new bone, soft tissue, and graft substitute material in the grafted region; (2) area fraction of bone and soft tissue components in the residual alveolar ridge compartment; and (3) the percentage of surface contact between the graft substitute material and new bone. Results: Measurable biopsies were available from 56% of the test and 81.8% of the control sites. Histology showed close contact between new bone and graft particles for both groups, with no significant differences in the amount of mineralized bone (21.6±10.0% for BCP vs. 19.8±7.9% for ABB; P=0.53) in the biopsy treatment compartment of test and control site. The bone‐to‐graft contact was found to be significantly greater for ABB (48.2±12.9% vs. 34.0±14.0% for BCP). Significantly less remaining percentage of graft substitute material was found in the BCP group (26.6±5.2% vs. 37.7±8.5% for ABB; P=0.001), with more soft tissue components (46.4±7.7% vs. 40.4±7.3% for ABB; P=0.07). However, the amount of soft tissue components for both groups was found not to be greater than in the residual alveolar ridge. Discussion: Both ABB and BCP produced similar amounts of newly formed bone, with similar histologic appearance, indicating that both materials are suitable for sinus augmentation for the placement of dental implants. The potential clinical relevance of more soft tissue components and different resorption characteristics of BCP requires further investigation.     

Effect of anorganic bovine bone to autogenous cortical bone ratio upon bone remodeling patterns following maxillary sinus augmentation

Introduction: Maxillary sinus augmentation is a predictable implant site development technique, although several local and systemic factors may influence outcomes. The aim of this study was to evaluate healing patterns and bone remodeling activity following the use of two different graft mixtures for maxillary sinus augmentation. Materials and methods: Patients in need of maxillary sinus augmentation were randomly assigned to two different groups. A graft mixture using a 50% autologous bone (AB) to 50% anorganic bovine bone (ABB) ratio was used in group 1, while a 20% AB to 80% ABB ratio was utilized for group 2. After a 6‐month healing period, bone core biopsies were harvested for histological, histomorphometrical, and immunohistochemical analyses. Results: Twenty‐eight subjects participated in this study. No statistically significant differences were found between groups in regards to vital bone and non‐mineralized tissue proportions. Higher number of osteoid lines (18.05 ± 10.06 in group 1 vs. 9.01 ± 7.53 in group 2; P=0.023) and higher cellularity, particularly regarding the number of osteocytes (631.85 ± 607.98 in group 1 vs. 219.08 ± 103.26 in group 2; P=0.002), were observed in specimens from group 1. Differences in expression patterns of osteopontin and tartrate‐resistant acid phosphatase were also detected between groups. Conclusion: AB to ABB ratio appears to influence bone remodeling patterns and cell content following maxillary sinus augmentation procedures. Similar proportion of vital bone was found in specimens obtained from both groups. More cellular presence was observed in samples containing higher proportions of AB. To cite this article:
Galindo‐Moreno P, Moreno‐Riestra I, Avila G, Padial‐Molina M, Paya JA, Wang H‐L, O'Valle F. Effect of anorganic bovine bone to autogenous cortical bone ratio upon bone remodeling patterns following maxillary sinus augmentation.
Clin. Oral Impl. Res. 22 , 2011; 857–864.
doi: 10.1111/j.1600‐0501.2010.02073.x     

Sinus bone formation and implant survival after sinus membrane elevation and implant placement: a 1- to 6-year follow-up study

Objectives: To investigate the long‐term clinical and radiographic results of the maxillary sinus membrane elevation technique where implants were inserted in a void space created by the elevation of the sinus membrane without adding any graft material. Materials and methods: A total of 84 patients were subjected to 96 membrane elevation procedures and simultaneous placement of 239 implants. Changes of intra‐sinus and marginal bone height in relation to the implants were measured in intraoral radiographs taken at insertion, after 6 months of healing, after 6 months of loading and then annually. Computerized tomography was performed pre‐surgically and 6 months post‐surgically. Resonance Frequency Analyses measurements were performed at the time of implants placement, at abutment connection and after 6 months of loading. The implant follow‐up period ranged from a minimum of one to a maximum of 6 years after implants loading. Results: All implants were stable after 6 months of healing. A total of three implants were lost during the follow‐up period giving a survival rate of 98.7%. Radiography demonstrated on average 5.3±2.1 mm of intra‐sinus new bone formation after 6 months of healing. RFA measurements showed adequate primary stability (implant stability quotient 67.4±6.1) and small changes over time. Conclusion: Maxillary sinus membrane elevation and simultaneous placement of implants without the use of bone grafts or bone substitutes result in predictable bone formation with a high implant survival rate of 98.7% during a follow‐up period of up to 6 years. The intra‐sinus bone formation remained stable in the long‐term follow‐up. It is suggested that the secluded compartment allowed for bone formation according to the principle of guided tissue regeneration. The high implant survival rate of 98.7% indicated that the implants sufficiently supported the fixed bridges throughout the study period. This technique reduces the risks for morbidity related to harvesting of bone grafts and eliminates the costs of grafting materials. To cite this article:
Cricchio G, Sennerby L, Lundgren S. Sinus bone formation and implant survival after sinus membrane elevation and implant placement: a 1‐ to 6‐year follow‐up study.
Clin. Oral Impl. Res. 22 , 2011; 1200–1212.
doi: 10.1111/j.1600‐0501.2010.02096.x     

A prospective,randomized pilot study on the safety and efficacy of recombinant human growth and differentiation factor‐5 coated onto β‐tricalcium phosphate for sinus lift augmentation

Objectives: The aim of this prospective, randomized clinical trial was to investigate the potential of recombinant human growth and differentiation factor‐5 (rhGDF‐5) coated onto β‐tricalcium phosphate (β‐TCP) (rhGDF‐5/β‐TCP) to support bone formation after sinus lift augmentation. Material and methods: In total, 31 patients participated in this multicenter clinical trial. They required a two‐stage unilateral maxillary sinus floor augmentation (residual bone height <5 mm). According to a parallel‐group design, the patients were randomized to three treatment groups: (a) augmentation with rhGDF‐5/β‐TCP and a 3‐month healing period, (b) augmentation with rhGDF‐5/β‐TCP and a 4‐month healing period and (c) medical device β‐TCP mixed with autologous bone and a 4‐month healing period. The primary study objective was the area of newly formed bone within the augmented area as assessed by histomorphometric evaluation of trephine bur biopsies. Results: The osseous regeneration was similar in each treatment group; the amount of newly formed bone ranged between 28% (± 15.5%) and 31.8% (± 17.9%). Detailed analysis of histological data will be published elsewhere. As secondary efficacy variables, the augmentation height at the surgery site was measured by radiography. The largest augmentation was radiologically achieved in the rhGDF‐5/β‐TCP – 3‐month and the rhGDF‐5/β‐TCP – 4‐month treatment groups. As safety parameters, adverse events were recorded and anti‐drug antibody levels were evaluated. Most of the adverse events were judged as unrelated to the study medication. Four out of 47 (8.5%) implants failed in patients treated with rhGDF‐5/β‐TCP, a result that is in agreement with the general implant failure rate of 5–15%. Transiently very low amounts of anti‐rhGDF‐5 antibodies were detected in some patients who received rhGDF‐5, which was not related to the bone formation outcome. Conclusion: rhGDF‐5/β‐TCP was found to be effective and safe as the control treatment with autologous bone mixed β‐TCP in sinus floor augmentation. Thus, further investigation regarding efficacy and safety will be carried out in larger patient populations. To cite this article:
Koch FP, Becker J, Terheyden H, Capsius B, Wagner W, on behalf of the research group of this multicenter clinical trial. A prospective, randomized pilot study on the safety and efficacy of recombinant human growth and differentiation factor‐5 coated onto β‐tricalcium phosphate for sinus lift augmentation.
Clin. Oral Impl. Res. 21 , 2010; 1301–1308.
doi: 10.1111/j.1600‐0501.2010.01949.x     

Maxillary sinus floor elevation using a tissue-engineered bone complex with β-TCP and BMP-2 gene-modified bMSCs in rabbits

Objectives: To study the effects of maxillary sinus floor elevation by a tissue‐engineered bone complex with β tricalcium phosphate (β‐TCP) and bone morphogenetic protein‐2 (BMP‐2) gene‐modified bone marrow stromal cells (bMSCs) in rabbits. Material and methods: bMSCs derived from New Zealand rabbit bone marrow were cultured and transduced with the adenovirus with BMP‐2 (AdBMP‐2), adenovirus with enhanced green fluorescent protein gene (AdEGFP) in vitro. Gene transfer efficiency was detected by EGFP expression. These gene‐modified autologous bMSCs were then combined with a β‐TCP granule scaffold at a concentration of 2 × 10⁷ cells/ml and used to elevate the maxillary sinus floor in rabbits. Twenty rabbits were randomly allocated into groups and sacrificed at weeks 2 and 8. For each time point, 20 maxillary sinus floor elevation surgeries were made bilaterally in 10 rabbits for the following groups (n=5 per group): group A (β‐TCP alone), group B (untransduced bMSCs/β‐TCP), group C (AdEGFP–bMSCs/β‐TCP), and group D (AdBMP‐2–bMSCs/β‐TCP). All samples were evaluated by histology and histomorphometric analysis. The fate of implanted bMSCs was traced initially by a confocol fluorescent microscope in the AdEGFP group. Results: Gene transfer efficiency reached up to 60–80% with 50 PFU/cell transduction as demonstrated by fluorescent microscopic analysis in the AdEGFP group. The augmented maxillary sinus height was maintained for the four groups till 8 weeks post‐surgery, while new bone area increased over the time. At week 2, bone areas in groups B–D were significantly larger than those in group A, while at week 8, in group D, the BMP‐2 gene‐enhanced tissue‐engineered bone had the largest bone area among the groups (P<0.05, ANOVA). In that group, a mature bone structure was detected in the center of the elevated space. Under a confocal microscope, green fluorescence in newly formed bone was observed for the EGFP group, which suggested that those implanted bMSCs might have contributed to the new bone formation. Conclusion: bMSCs modified with the AdBMP‐2 gene can promote new bone formation and maturation in the rabbit maxillary sinus. BMP‐2 regional gene therapy and a tissue engineering technique could be effectively used in maxillary sinus elevation and bone regeneration.     

Volumetric changes of the graft after maxillary sinus floor augmentation with Bio-Oss and autogenous bone in different ratios: a radiographic study in minipigs

Objective: The objective of the present study was to learn about the volumetric changes of the graft after maxillary sinus floor augmentation with Bio‐Oss and autogenous bone from the iliac crest or the mandible in different ratios in minipigs. Material and methods: Bilateral maxillary sinus floor augmentation was performed in 40 minipigs with: (A) 100% autogenous bone, (B) 75% autogenous bone and 25% Bio‐Oss, (C) 50% autogenous bone and 50% Bio‐Oss, (D) 25% autogenous bone and 75% Bio‐Oss, and (E) 100% Bio‐Oss. The autogenous bone graft was harvested from the iliac crest or the mandible and the graft composition was selected at random and placed concomitant with implant placement. Computed tomographies of the maxillary sinuses were obtained preoperatively, immediately postoperatively, and at euthanasia after 12 weeks. The volumetric changes of the graft were estimated using the Cavalieri principle and expressed as mean percentage with a 95% confidence interval (CI). Results: The mean volume of the graft was reduced by (A) 65% (95% CI: 60–70%), (B) 38% (95% CI: 35–41%), (C) 23% (95% CI: 21–25%), (D) 16% (95% CI: 12–21%), and (E) 6% (95% CI: 4–8%). The volumetric reduction was significantly influenced by the ratio of Bio‐Oss and autogenous bone (P<0.001), but not by the origin of the autogenous bone graft (P=0.2). Conclusions: The volume of autogenous bone grafts from the iliac crest and the mandible is reduced significantly after maxillary sinus floor augmentation in minipigs. The graft volume is better preserved after the addition of Bio‐Oss and the volumetric reduction is significantly influenced by the ratio of Bio‐Oss and autogenous bone. However, further studies are needed addressing the amount of new bone formation and bone‐to‐implant contact before the final conclusion can be made about the optimal ratio of Bio‐Oss and autogenous bone. To cite this article:
Jensen T, Schou S, Svendsen PA, Forman JL, Gundersen HJG, Terheyden H, Holmstrup P. Volumetric changes of the graft after maxillary sinus floor augmentation with Bio‐Oss and autogenous bone in different ratios: a radiographic study in minipigs.
Clin. Oral Impl. Res. 23 , 2012; 902–910
doi: 10.1111/j.1600‐0501.2011.02245.x