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     

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

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

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