Construction of an experimental millerⅢ gingival retraction animal model in beagle dogs

Objective To construct a Miller class Ⅲ gingival recession animal model and to lay the foundation for exploring the treatment of Miller class Ⅲ gingival recession. Methods Two adult male beagle dogs were selected, and four teeth from each beagle dog were selected to establish an experimental Miller class Ⅲ gingival recession model. The root surface was revealed by removing the soft and hard tissues of the buccal side. The success of the model was deter⁃ mined by measuring the vertical gingival retraction (VGR), horizontal retraction (HGR), keratosis tissue width (KTW), gingival tissue thickness (GTT), and probing depth (PD) at 1, 2, 4, 6, and 8 weeks after modeling. Results After ob⁃ serving the clinical indexes, the PDs before and after the modeling were all smaller than 3 mm and no deep⁃period pock⁃ets were formed. The VGR before modeling was 0 mm, and the VGR range after modeling was 5⁃6.38 mm. A compari⁃ son of the before and after modeling results showed that this difference was statistically significant (P < 0.05). The post⁃ operative VGR results were grouped according to timepoint. A comparison between the two groups showed that the dif⁃ ferences at 2, 4, 6 and 8 weeks postoperatively were not statistically significant (P > 0.05). The HGR before the model⁃ ing was 0 mm, and the HGR fluctuated around 10.5 mm after the modeling, and this difference was statistically signifi⁃ cant (P < 0.05). The HGR results were grouped by timepoint after surgery, and a one⁃way analysis of showed that the differences between the two groups were not statistically significant (P > 0.05). The KTW range before modeling was 6～ 9 mm, and it fluctuated around 2 mm after modeling, and this difference was statistically significant (P < 0.05). The KTW results were grouped by timepoint after surgery, and they indicated that significant differences did not occur be⁃ tween the groups postoperatively (P > 0.05). The pre⁃modeling GTT was 1.5 mm, and the GTT range after modeling was 1.5⁃2 mm. The preoperative and postoperative GTT results were grouped by timepoint, and the results showed that sig⁃ nificant differences did not occur between 1 week and 2 weeks after surgery (P = 0.123), although a statistically signifi⁃ cant difference was observed at 1 week postoperatively between this group and the other groups (P < 0.05). Conclu⁃ sion The method used in this experiment can successfully build a Miller class III gingival recession animal model, and the model remains stable after wound healing.