Distraction osteogenesis in dog with a tooth-borne device: Histological and histomorphometric analysis

Evaluation of flat ridge rehabilitation using an intraoral custom-made distraction device at four weeks versus eight weeks and its impact on dental implant efficacy: A comparative study

Background

This study aimed to evaluate alveolar bone height enhancement using a custom-made distractor to evaluate its ability to support dental implants.

Method

The left mandibular premolars of nine dogs were extracted, followed by alveoloplasty to simulate an atrophic ridge. The dogs were divided into three groups: groups I and II received distractors followed by dental implants, while group III received implants alone. Distractors remained in place for 4 weeks in group I and 8 weeks in group II for consolidation. Subsequently, the distractors were removed, and a titanium dental implant was immediately inserted during the same visit. In the third group, implants were placed in the same area as noted. The implant was left in position for 8 weeks, after which the left hemimandible underwent dual-energy X-ray absorptiometry and histological analysis, focusing on the region of interest (ROI) mesial and distal to the dental implant.

Results

Densitometric analysis revealed notable osseointegration between the regenerated bone adjacent to the dental implant. Notably, there were significant differences in osseointegration between groups I and II. Moreover, osseointegration levels were similar between groups II and III, where no distraction device was employed. Histological findings showed the formation of new bone in the distraction gap, with more advanced maturation noted in the 8-week group. It is worth noting that the integration between bone and implants in the third group surpasses that of the distraction groups.

Conclusion

Using the distraction device for only 4 weeks is acceptable to meet the criteria for implant placement. The small size of the distraction device reduces tissue reaction after surgery because it eliminates the necessity of complex surgeries that may require bone grafting. Density measurements and histological observations indicate that the distractor promotes the generation of enough bone for prosthetic rehabilitation with dental implants.

Experimental Design of Vertical Distraction Osteogenesis Using Simple 3 Screws

Distraction osteogenesis devices are complicated. To simplify these devices, we used 3 simple screws and 1 rubber band to realize the idea and analyzed histologic changes induced by mechanical forces. Ten female New Zealand white rabbits were studied. A left or right side of the mandible was randomly selected as the experimental side (ES). The unilateral mandible was distracted, and 2 fixation screws and 1 traction screw were implanted. When the traction screw was rotated downward, the opposite force made the osteotomy block move in opposite directions to increase the bone height. The control side (CS) was not processed. The results were assessed after 20 days of traction. Bone height in the ES increased by 5 mm. Toluidine blue staining showed that the number of osteoblasts per unit area on the ES was higher than that of the CS (P<0.01). PerkinElmer showed that the expressions of proliferating cell nuclear antigen (P=0.016) and collagen-I (P=0.000) on the ES were higher than those on the CS. Transmission electron microscopy showed that the number of mitochondria, endoplasmic reticulum, and Golgi apparatus on the ES was significantly greater than the CS. The results confirmed that the 3 screws vertically increase the bone height. Mechanical force signals stimulate tissue activity and lead to significant cell proliferation and differentiation in the traction zone. Collagen-I may induce osteogenesis in the early stage of traction.