Phenotypes of CCAAT/enhancer-binding protein beta deficiency: Hyperdontia and elongated coronoid process

Objectives: This investigation aimed to conduct a case-control study of mandibular morphology and dental anomalies to propose a relationship between mandibular/dental phenotypes and deficiency of CCAAT/enhancer-binding protein beta (CEBPB). Materials and methods: Skulls of CEBPB^-/-, CEBPB^+/- and CEBPB^+/+ mice were inspected with micro-computed tomography. Mandibular morphology was assessed with a method of Euclidean distance matrix analysis. Results: Elongation of the coronoid process was identified in CEBPB^+/- (P≤0.046) and CEBPB^-/- 12-month-olds (P≤0.028) but not in 14-day-olds (P≥0.217) and 0-day-olds (P≥0.189) of either genotype. Formation of supernumerary teeth in CEBPB^-/- adult mice was demonstrated (χ²=6.00, df=1, P=0.014). Conclusions: CEBPB deficiency was related to elongation of the coronoid process and formation of supernumerary teeth. The mandibular and dental phenotypes of CEBPB deficiency were unseen by the 14th day after birth. Future investigations into the influence of CEBPB on mandibular and dental development are needed.