Mats Hallman

Histological and histomorphometrical analyses of biopsies harvested 11 years after maxillary sinus floor augmentation with deproteinized bovine and autogenous bone

OBJECTIVEnThe purpose of the present study was to histologically and histomorphometrically evaluate the long-term tissue response to deproteinized bovine bone (DPBB) particles used in association with autogenous bone and to compare particle size after 6 months and 11 years, in the same patients, in order to determine possible resorption.nnnMATERIAL AND METHODSnTwenty consecutive patients (14 women and six men) with a mean age of 62 years (range 48-69 years) with severe atrophy of the posterior maxilla were included in this study. Thirty maxillary sinuses with <5 mm subantral alveolar bone were augmented with a mixture of 80% DPBB and 20% autogenous bone. Eleven years (mean 11.5 years) after augmentation, biopsies were taken from the grafted areas of the 11 patients who volunteered to participate in this new surgical intervention. The following histomorphometrical measurements were performed in these specimens: total bone area in percentage, total area of the DPBB, total area of marrow space, the degree of DPBB-bone contact (percentage of the total surface length for each particle), the length of all DPBB particles and the area of all DPBB particles. The length and the area of the particles were compared with samples harvested from the same patients at 6 months (nine samples) and pristine particles from the manufacturer.nnnRESULTSnThe biopsies consisted of 44.7+/-16.9% lamellar bone, 38+/-16.9% marrow space and 17.3+/-13.2% DPBB. The degree of DPBB to bone contact was 61.5+/-34%. There were no statistically significant differences between the length and area of the particles after 11 years compared with those measured after 6 months in the same patients or to pristine particles from the manufacturer.nnnCONCLUSIONnDPBB particles were found to be well integrated in lamellar bone, after sinus floor augmentation in humans, showing no significant changes in particle size after 11 years. To cite this article: Mordenfeld A, Hallman M, Johansson CB, Albrektsson T. Histological and histomorphometrical analyses of biopsies harvested 11 years after maxillary sinus floor augmentation with deproteinized bovine and autogenous bone.

A Prospective 1-Year Clinical and Radiographic Study of Implants Placed after Maxillary Sinus Floor Augmentation with Synthetic Biphasic Calcium Phosphate or Deproteinized Bovine Bone

BACKGROUNDnThe technique of using bone grafts or different biomaterials for augmentation of the maxillary sinus prior to implant placement is well accepted by clinicians. However, clinical documentation of some bone substitutes is still lacking.nnnPURPOSEnThis prospective study was designed to evaluate the success rate of implants placed after maxillary sinus augmentation with a novel synthetic biphasic calcium phosphate (BCP) or deproteinized bovine bone (DBB), the latter acting as control.nnnMATERIAL AND METHODSnNine edentulous patients and two partially edentulous patients with a mean age of 67 years with a bilateral need for sinus augmentation, < 5 mm residual bone in the floor of the sinus and a crestal width ≥ 4 mm, were included in the study. After bilateral elevation of the Schneiderian membrane, all patients were randomized for augmentation with synthetic BCP in one side and DBB in the contralateral side. After 8 months of graft healing, 62 implants with an SLActive surface were placed. Implant survival, graft resorption, plaque index, bleeding on probing, sulcus bleeding index, probing pocket depth, and implant success rate were evaluated after 1 year of functional loading.nnnRESULTSnAfter a mean of 118 days, all patients received their fixed prosthetic constructions. One implant was lost in each biomaterial, giving an overall survival rate of 96.8%. Success rates for implants placed in BCP and DBB were 91.7 and 95.7%, respectively. No significant difference in marginal bone loss was found around implants placed in BCP, DBB, or residual bone, respectively. The mean graft resorption was 0.43 mm (BCP) and 0.29 mm (DBB).nnnCONCLUSIONnIn this limited study, implant success rate was not dependent on the biomaterial used for maxillary sinus augmentation. Similar results were found after 1 year of functional loading for implants placed after sinus augmentation using BCP or DBB.

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

OBJECTIVESnTo compare resorption of a synthetic biphasic calcium phosphate (BCP) bone-graft substitute with deproteinized bovine bone (DBB) used for human maxillary sinus augmentation.nnnMATERIALS AND METHODSnEleven patients underwent bilateral maxillary sinus floor augmentation with DBB in one side and a BCP (40%beta-tricalcium phosphate (beta-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.nnnRESULTSnResidual graft material of both types was present as 10-500 mum 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 beta-TCP and reprecipitation on the surface of calcium-deficient hydroxyapatite.nnnCONCLUSIONnThe beta-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.

A randomized and controlled clinical trial of two different compositions of deproteinized bovine bone and autogenous bone used for lateral ridge augmentation

OBJECTIVEnThe aim of the study was to radiologically and histologically evaluate the graft healing and volumetric changes after lateral augmentation with two different compositions of deproteinized bovine bone (DPBB) and autogenous bone (AB).nnnMATERIAL AND METHODSnThirteen patients with a mean age of 59.6xa0±xa012.1xa0years (six men and seven women) were included in this randomized and controlled trial, designed as a split-mouth study. Ten edentulous and four partially edentulous jaws with an alveolar ridge width of ≤4xa0mm were laterally augmented with a graft composition of 60xa0:xa040 (DPBB/AB) on one side and 90xa0:xa010 (DPBB/AB) on the contralateral side. Cone beam computed tomography (CB/CT) was obtained immediately postoperatively and after a healing period of 7.5xa0months. Width changes were measured on CB/CT scans. After a mean healing period of 8.1xa0months (range, 7.9-8.3), biopsies were retrieved perpendicular to the crest from each graft by means of a trephine bur. Histomorphometry was performed, and the following variables were recorded: Ingrowth of new bone (percentage of total graft width), percentage of DPBB, bone and soft tissue, and percentage of DPBB particles in contact with bone.nnnRESULTSnThe mean gained width of the alveolar crest after 7.5xa0months was significantly more for the 60xa0:xa040 mixture compared with the 90xa0:xa010 mixture, 3.5 (±1.3) mm and 2.9 (±1.3) mm, respectively. There was a significant difference in graft width reduction between 60xa0:xa040 and 90xa0:xa010 after 7.5xa0months, 37 (±19.9)% and 46.9 (±23.5)%, respectively. New bone ingrowth had occurred in 82.1 (±23.3)% and 82.3 (±26.6)% of the graft, respectively. There were no statistical differences between fractions of different tissues between the 90xa0:xa010 and 60xa0:xa040 compositions. However, there were significantly more soft tissue and less new bone formation closer to the periosteum compared with the graft portion closer to the residual bone in both 60xa0:xa040 and 90xa0:xa010 compositions.nnnCONCLUSIONSnThere was significantly less graft width reduction with a mixture of 60xa0:xa040 (DPBB/AB) compared with a mixture of 90xa0:xa010 composition, but the results from the histomorphometry showed no statistical differences comparing the groups.

A 10-Year Clinical and Radiographic Study of Implants Placed after Maxillary Sinus Floor Augmentation with an 80:20 Mixture of Deproteinized Bovine Bone and Autogenous Bone

BACKGROUNDnThere is a need for prospective, long-term follow-up studies of implants placed after maxillary sinus floor augmentation (MSFA).nnnPURPOSEnThe aim of the present study was to determine whether deprotenized bovine bone (DPBB) used for MSFA may result in long-term stability of placed dental implants.nnnMATERIAL AND METHODSnFourteen of the 20 patients included in the study were followed throughout the 10 years study period. These patients had 53 implants placed in 22 (6 unilateral and 8 bilateral) maxillary sinuses augmented with a mixture of 80% DPBB and 20% autogenous bone (80:20), and 15 implants placed in non-grafted sites. Clinical and radiographic examinations of the implants and grafts were performed.nnnRESULTSnAfter 10 years of functional loading 15 of the initially placed 108 implants had been lost giving a cumulative survival rate of 86%. The mean marginal bone loss was 1.6 ± 1.0 mm. There were no statistically significant differences in marginal bone level, pocket depth, or ISQ-values between implants placed in residual or grafted bone or between smokers or non-smokers at 10 years follow-up. There was a statistically significant reduction (p < .01) in graft height between 3 months and 2 years but no further significant reduction up to 10 years.nnnCONCLUSIONSnThe first 2 years after placement of implants with turned surfaces placed in sites after sinus floor augmentation with DPBB and autogenous bone seem to be critical for implant survival. At 10 years follow-up, the remaining implants presented excellent clinical and radiological results regardless of smoking habits or implant sites (augmented or residual bone).

Bone replacement following dental trauma prior to implant surgery : present status

Dento-alveolar trauma often leads to a need for reconstruction of the alveolar crest before an implant can be placed. Although autogenous bone grafts is considered the gold standard, this may be associated with patient morbidity and graft resorption. Consequently, the use of bone substitutes has increased. Today, a substantial number of biomaterials are available on the market, but only a few are well documented. The user should be aware that these biomaterials have different properties: resorbable or non-resorbable, time of resorption and resorption mechanism. The purpose of this review is to describe the function of various bone substitutes and indications for their use in reconstructive implant surgery and to give an overview of the current situation.

A Clinical and Histological Case Series Study on Calcium Sulfate for Maxillary Sinus Floor Augmentation and Delayed Placement of Dental Implants

BACKGROUNDnMaxillary sinus floor augmentation is a procedure that is indicated in cases when the volume of the posterior maxillary bone is inadequate. The goal of this treatment is to obtain sufficient amount of bone tissue in order to gain osseointegration of endosseous implants.nnnPURPOSEnThe purpose of this study was to conduct a clinical and histological analysis of calcium sulfate (CaS) as bone graft substitute in sinus floor augmentation.nnnMATERIAL AND METHODSnTen patients with edentulous maxillas were included in this study. They had moderate to severe atrophy of the posterior maxilla. Surgiplaster (Classimplant®, Rome, Italy) was used as graft material in the maxillary sinus and was covered by BioGide® (Geistlish Pharmaceutical, Wolhusen, Switzerland). After 4 months of graft healing, 40 dental implants were placed and a biopsy for histomorphometry was taken at these occasions. The specimens were viewed by light microscope, and the extent of bone regeneration and remaining graft material was evaluated. Radiographs were taken at the time of sinus augmentation and after 4 months of graft healing.nnnRESULTSnAt the time of abutment surgery, one implant was considered as a failure and was consequently removed, giving a survival rate of 97.5% after 1 year of loading. Radiographs showed a mean of 26.5% shrinkage of the augmented area. A significant resorption of CaS was noted with a mean value of 8.8% of remaining graft material after 4 months of healing. The biopsies also revealed new bone formation with a mean value of 21.2% of the total biopsy area. Histology showed signs of an acellular substitution of CaS with bone-like tissue.nnnCONCLUSIONnThe results of this study show that new bone regeneration occurs in the maxillary sinus after augmentation with CaS. This enabled successful placement, integration, and loading of dental implants in the posterior maxilla, as only 1 of 40 implants was lost during 1 year of follow-up.

Sinus Floor Augmentation Using Straumann® BoneCeramic™ and Bio-Oss® in a Split Mouth Design and Later Placement of Implants: A 5-Year Report from a Longitudinal Study

BACKGROUNDnStraumann® BoneCeramic™ is a synthetic biphasic calcium phosphate (BCP) aimed for sinus floor augmentation. Long-term follow-up of implants placed in BCP after sinus augmentation is still missing.nnnPURPOSEnThe primary aim of the study was to compare survival rates and marginal bone loss of Straumann SLActive implants placed in either BCP (test) or Bio-Oss® (DBB) (control) after sinus floor augmentation. The secondary aim was to calculate graft sinus height at different time points.nnnMATERIALS AND METHODSnBilateral sinus floor augmentation was performed in a split mouth model. Eleven patients (mean age 67 years) received 100% BCP on one side and 100% DBB on the contralateral side. After 8 months of graft healing, 62 Straumann SLActive implants were placed. After 5 years of functional loading (6 years after augmentation) of implants, marginal bone levels and grafted sinus height were measured, and implant survival and success rates were calculated.nnnRESULTSnAfter 5 years of loading, all prosthetic constructions were in function although two implants were lost in each grafting material. The overall implant survival rate was 93.5% (91.7% for BCP, 91.3% for DBB, and 100% for residual bone). The success rates were 83.3% and 91.3% for BCP and DBB, respectively. There was no statistically significant difference in mean marginal bone level after 5 years between BCP (1.4u2009±u20091.2u2009mm) and DBB (1.0u2009±u20090.7u2009mm). Graft height reduction (GHR) after 6 years was limited to 6.6% for BCP and 5.8% for DBB.nnnCONCLUSIONnIn this limited RCT study, the choice of biomaterial used for sinus floor augmentation did not seem to have any impact on survival rates and marginal bone level of the placed implants after 5 years of functional loading and GHR was minimal.

Tissue reactions to subperiosteal onlays of demineralized xenogenous dentin blocks in rats

OBJECTIVESnThis study was undertaken to examine the influence of partial demineralization of xenogenous dentin on bone formation in an osteoconductive environment.nnnMATERIALS AND METHODSnSixty dentin blocks, 2-3 mm thick and 4 mm in diameter, were prepared from developing teeth of young pigs. Forty blocks were demineralized in 24% ethylenediaminetetraacetic acid (pH 7.0) for 1, 2, 6 or 12 h. Forty adult rats divided into eight groups with five rats in each group were used. A sagittal midcranial incision was made from the occipital to the frontal region. Through a subperiostal dissection, a pocket was created on each side of the skull. One demineralized block was placed on one side, and a non-demineralized block was placed on the contralateral side, or the pocket was left empty as controls. Thus, eight experimental groups with five rats in each were formed.nnnRESULTSnResorption increased significantly with increasing degree of demineralization while bone formation increased significantly with increasing degree of demineralization, provided inflammation was compensated for. This suggests an important role for inflammation or infection control during the healing period of osteogenic implants to optimize osseous integration in an osteoconductive environment.nnnCONCLUSIONnPartial demineralization of xenogenous dentin blocks may provide a method for optimizing the integration of dentin onlays in an osteoconductive environment, thus stabilizing the implant and slowing down replacement resorption.

A systematic review and meta-analysis of long-term studies (five or more years) assessing maxillary sinus floor augmentation

The objective was to test the hypothesis of no difference in long-term (≥5 years) implant treatment outcomes after maxillary sinus floor augmentation (MSFA) with autogenous bone graft compared to a mixture of autogenous bone graft and bone substitutes or bone substitutes alone. A MEDLINE (PubMed), Embase, and Cochrane Library search in combination with a hand-search of relevant journals was conducted. Human studies published in English between January 1, 1990 and October 1, 2016 were included. Nine studies fulfilled the inclusion criteria. The survival of suprastructures has never been compared within the same study. The 5-year implant survival after MSFA with autogenous bone graft was 97%, compared to 95% for Bio-Oss; the reduction in vertical height of the augmented sinus was equivalent with the two treatment modalities. Non-comparative studies demonstrated high survival rates for suprastructures and implants regardless of the grafting material used. Meta-analysis revealed an overall estimated patient-based implant survival of 95% (confidence interval 0.92-0.96). High implant stability quotient values, high patient satisfaction, and limited peri-implant marginal bone loss were revealed in non-comparative studies. No long-term randomized controlled trial comparing the different treatment modalities was identified. Hence, the conclusions drawn from the results of this systematic review should be interpreted with caution.