Introduction: Mandibular fractures comprise most of the traumatic injuries treated by an oral and maxillofacial surgeon. The aim of fracture treatment is to restore the architecture and function of bone.  Many techniques for treating mandibular fractures have evolved over the years. The design of the three dimensional (3D) plate is conceptually that of 2 linear plates connected by reinforcing vertical struts providing greater resistance against gap opening at the inferior border with biting forces. Objectives: To compare histologically bone healing of mandibular body osteotomy after using either a 3D miniplate or conventional miniplates. Materials and methods: This study was conducted on twelve healthy dogs. An iatrogenic osteotomy defect was performed intra-orally between the mandibular 3rd and 4th premolars using a surgical micro reciprocating saw. The fragments will be reduced bimanually and stabilized:  Group A (six dogs): 3D miniplates. Group B (six dogs): conventional miniplates.  The dogs were euthanized at 2 and 6 weeks postoperatively and the osteotomy sites were excised, divided into three thirds (Tension Third, TT; Intermediary Third, IT; Compression Third, CT) and prepared for histological analysis. Results:The osteotomy site was completely filled with parallel-fibred bone, with more newly formed Haversian systems in Group A compared with Group B, bone repair did not reach the typical aspects of the parent lamellar bone. The percentages of newly formed bone at 2 weeks in group A according to thirds (TT, IT and CT) that reported have a statistically significant difference in comparison with group B. At 6 weeks, there were no statistically significant differences between the two groups among the TT and CT but there was a statistically significant difference (p4 = 0.039) in the IT. Conclusions: 3-D plates could be a better option than conventional miniplates.