A new standardized critical size bone defect model in the pig forehead for comparative testing of bone regeneration materials



The preclinical study aimed to establish a standardized preclinical model to investigate osseous graft consolidation in defect configurations of limited regenerative capacity.

Material and methods

Critical size defects (CSD) were prepared and titanium tubes inserted for defect separation from local bone in the forehead area of 18 pigs. Defects were filled with demineralized bovine bone mineral (DBBM) or served as empty controls and were covered with a resorbable collagen membrane (CM) or left untreated. Six randomly selected pigs were sacrificed after 4, 8 and 12 weeks. Specimens were histologically and histomorphometrically analysed focusing on newly formed bone (NFB), demineralized bovine bone mineral (DBBM) and soft tissue (ST) proportions.


Four weeks after defect preparation, no statistically significant difference concerning NFB quantity could be detected within the groups. Defects covered with the CM showed lower amounts of DBBM. After 6 and 12 weeks, defects augmented with DBBM in combination with a CM (8 weeks: 43.12 ± 4.31; 12 weeks: 43.05 ± 3.01) showed a statistically significant higher NFB rate compared to empty control defects covered with 8 weeks: 7.66 ± 0.59; 12 weeks or without a CM; 8 weeks: 8.62 ± 2.66; 12 weeks: 18.40 ± 2.40. CM application showed no significant impact on osseous defect regeneration or soft tissue formation. Superior NFB could be detected for basal aspect for several evaluation time points.


The modification of CSD with titanium tubes represents a suitable model to imitate a one-wall defect regeneration situation.

Clinical relevance

The established model represents a promising method to evaluate graft consolidation in one-wall defect configuration.

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The study was undertaken in cooperation with the Semmelweis-University, Budapest, Hungary. Animal care keeping and surgical procedures were performed in the laboratories of the Semmelweis-University, Budapest, Hungary. Specimen processing was done in the laboratories of the Department of Oral and Maxillofacial Surgery, University of Erlangen-Nürnberg, Erlangen, Germany. Geistlich Pharma AG, Wolhusen, Switzerland, supported this study. The authors have no conflicts of interest. The work of Dr. E. Felszeghy, A. Krautheim-Zenk and S. Schönherr is highly appreciated.


The work was supported by Geistlich Pharma AG, Wolhusen, Switzerland (KC 354-12036).

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Correspondence to Tobias Moest.

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Conflict of interest

Tobias Moest declares that he has no conflict of interest. Karl Andreas Schlegel declares that he has no conflict of interest. Marco Kesting declares that he has no conflict of interest. Matthias Fenner declares that he has no conflict of interest. Rainer Lutz declares that he has no conflict of interest. Daniele Machado Beck declares that she has no conflict of interest. Cornelius von Wilmowsky declares that he has no conflict of interest.

Ethical approval

The presented work was approved by the Pest county government department for food safety and animal health, Hungary (approval number: 1112/000/2003).

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Moest, T., Schlegel, K.A., Kesting, M. et al. A new standardized critical size bone defect model in the pig forehead for comparative testing of bone regeneration materials. Clin Oral Invest 24, 1651–1661 (2020). https://doi.org/10.1007/s00784-019-03020-w

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  • Critical size defect
  • Bone substitutes
  • Demineralized bovine bone mineral
  • Animal model