INTRODUCTION:Vitamin D3 insufficiency has become a severe health problem that affects more than one billion people worldwide. Maternal vitamin D3 deficiency can induce dentin defects during tooth development. OBJECTIVES: To evaluate the biological effect of maternal vitamin D3 deficiency on dentinogenesis of the rat offspring. MATERIALS AND METHODS: Twelve female Albino rats were used. Rats were divided randomly into two equal groups. In the control group, rats were fed normal balanced diet and exposed to the normal light/dark cycle. In the study group, rats were housed in incandescent light devoid of ultraviolet B-light and fed a diet free of vitamin D3.Vitamin D3 level in the serum was measured every two weeks till reached vitamin D3 deficiency. Female rats were mated to be pregnant. At the fourth day after labor, two pups were taken from the litter of each mother. The dentinogenesis of the developing mandibular first molars was examined by the light and transmission electron microscope and evaluated by histomorphometric analysis. RESULTS: Vitamin D3 deficiency harmfully affected odontoblast differentiation, dentin formation and mineralization. CONCLUSION: Maternal vitamin D3 deficiency during tooth development has an adverse effect on odontoblast differentiation, dentin formation and mineralization.

INTRODUCTION:Alveolar bone deficiency is one of most common problems encountered with oral rehabilitation. Many bone augmentation techniques have been documented, one of them is augmentation by bone grafting and barrier membranes, ceramic membrane proved efficiency in guided bone regeneration due to enhanced properties. AIM OF THIS STUDY: Evaluation of bone surface area under perforated ceramic membrane in relation to non perforated ceramic membrane. MATERIALS AND METHODS: 14 mongrel dogs divided into two equal groups, study group used bone graft, cortical perforation and perforated ceramic membrane, control group used bone graft, cortical perforation and non perforated ceramic membrane, follow up for 12 weeks and sacrification was done retrieving ceramic mebrane with samples of new bone which histologically prepared for histomorphometric analysis. Results: By histological evaluation more cellularity and vascularity, better trabecular arrangement and lesser granulation tissues were noted under perforated ceramic group. By histomorphometric analysis statistically significant at p ≤ 0.05 and higher bone surface area with mean value of 40.09 ± 3.50 associated with perforated group in comparison with mean value of 19.92 ± 3.63 associated with non perforated ceramic membrane group. CONCLUSION: Perforated ceramic membrane is comparable to occlusive one in terms of higher bone surface area, reduced granulation tissues and favorable blood supply.