Evaluation of 4 and 8 Weeks of Healing in a Murine Implant Model
Dental implants are increasing in prevalence as desirable options for replacing missing teeth. Unfortunately, implants come with complications, and animal models are crucial to studying the pathophysiology of complications. Current murine model experiments can be lengthy, with 8 weeks of extraction socket healing before implant placement. Therefore, we aimed to investigate the efficacy of decreasing extraction healing time from 8 to 4 weeks in a dental implant mouse model. Thirty-one 3-week-old C57BL/6J male mice underwent maxillary first and second molar extractions followed by 8 (control) or 4 (test) weeks of extraction socket healing before implant placement. Mice were euthanized after 4 weeks of implant osseointegration. Samples were analyzed via microcomputerized tomography and histology. When mice received implants 4 weeks after extractions, there was no statistical difference in initial bone crest remodeling or surrounding bone volume compared to those after 8 weeks of healing. Histologically, the hard and soft tissues surrounding both groups of implants displayed similar alveolar bone levels, inflammatory infiltrate, osteoclast count, and collagen organization. A 4-week extraction healing period can be utilized without concern for osseointegration in a murine implant model and is a viable experimental alternative to the previous eight weeks of healing. While small animal implant models are less directly applicable to humans, advancements in experimental methods will ultimately benefit patients receiving dental implants through improved prevention and treatment of complications. Subsequent research could investigate occlusal effects or whether healing time affects prognosis after induction of peri-implantitis.
A schematic diagram describing the timing of the experimental design.
(a) Representative sagittal micro-CT image showing orientation and location of linear bone height measurements surrounding dental implants. Measurements were taken mesial and distal to the implant, from the base of the implant head to the alveolar bone crest. (b) A representative micro-CT image of the implant shows the orientation and location of volumetric bone measurements for dental implants. The highlighted area represents the area considered in volumetric measurements.
Graphs reflecting the (a) averaged distance from the implant head to the alveolar bone crest (ABC) and (b) percent bone volume surrounding implants placed after 8 weeks vs 4 weeks of extraction socket healing. Percent bone volume quantified as bone volume/tissue volume (BV/TV) in mm3. Data is shown as mean ± SEM. P > .05. n ≥ 11 for all groups.
Representative sagittal H&E images of dental implants placed after 8 (a) vs 4 (b) weeks of extraction socket healing. 4× and 20× magnification. Note the comparable alveolar bone levels and inflammatory infiltrate.
Representative sagittal images of picrosirius red staining under light and dark filters of tissues surrounding implants placed after 8 (a) vs 4 (b) weeks of extraction socket healing. 4× and 20× magnification. Note the comparable collagen bundle organization.
Representative sagittal images of TRAP staining for osteoclast assessment surrounding dental implants placed after 8 (a) vs 4 (b) weeks of extraction socket healing. 4× and 20× magnification.
Contributor Notes