Establishing a new periodontitis-like intrabony maxillary defect in rats for investigation on bone regeneration

Abstract

The high incidence rate of periodontal bone defects and the unique regeneration characteristics of periodontal bone require a specially designed animal jawbone defect model to evaluate the appropriate periodontal bone regeneration procedure. The aim of the present investigation was to develop a reproducible, quantifiability and easy to implement periodontitis-like intrabony maxillary defect model in rats that allows investigation on bone regeneration. Ten upper jaws of rats were analyzed by micro-CT (µCT) imaging according to the bone dimensions for an appropriate position of a three-walled bone defect. A total of 30 intrabony defects measuring 1 × 1 × 1 mm were created using a split-mouth model on the palatal side of the maxillary first molar using ultrasonic surgery. 6 bone defects served as control. 20 bone defects were filled with alloplastic and xenogeneic particulate bone graft, and µCT scans were performed to verify bone regeneration of the periodontitis-like three-walled bone defect after 12 weeks. After 12 weeks, the µCT examinations showed sufficient bone regeneration of the artificially created periodontitis-typical defects. The µCT images revealed no morphological differences between xenogeneic and alloplastic bone substitute material. No restrictions for the animals, dehiscences or wound healing disorders were evident during the entire study period. The presented minimally invasive rat model with bilateral periodontitis-typical intrabony defects palatal to the first upper molar represents a favorable model for the investigation of regenerative osseous processes within a small defect.

Fig. 1

Postoperative visualization of a rat maxilla with created intrabony defects on both first upper molar without bone graft material reconstructed from µCT images.

Fig. 2

Photographic documentation of the individual surgical steps. a Representation of the incision, which is also illustrated by the yellow lines. The opposite side of the jaw has already been operated on the first molar and closed with sutures. b Blunt subperiosteal preparation and formation of a mucoperiosteal flap. c The artificially created three-walled intrabony defect. d Monitoring the defect size using a periodontal probe; e particulate bone substitute material inserted into the defect; f postoperative situation with tension-free adaptation of the wound edges and gingival suture.

Fig. 3

µCT images of intrabony defect in the sagittal plane with a control defect, b alloplastic and c xenogeneic bone graft after operation. Intrabony defect in the sagittal plane with d control defect, e alloplastic and f xenogeneic bone graft after 12 weeks. Graphical representation of absolute difference in bone reduction in g horizontal (**p = 0.002; ***p ≤ 0.001), h vertical (***p ≤ 0.001), and i sagittal plane (**p = 0.003; ***p ≤ 0.001).