A preliminary study of effects of immediate bone grafting at mandibular first molar fresh extraction socketon maintaining alveolar bone height in adult orthodontic patients

Abstract

Objective To evaluate the effect of immediate bone graftingat fresh mandibular first molar extraction socket on maintain alveolar bone height during orthodontic treatment.Methods 32 adult orthodontic patients withmandibular first molars extraction treatment plan were selected.Thetotal of 40 molar extraction sites were divided into graft group and non-graft group randomly.All patients received orthodontic treatment 2weeks after extraction (with or without bone graft).Cone beam CT were taken before (T0)and one year after extraction(T1).Compare the changes of alveolar height and width of two groups by Invivo Dental 5.0 software.Results One year after orthodontic treatment,extraction spacesingraft group and non-graft group decreased by an average of 2.85 mm and 3.50 mm respectively.In graft group,the alveolar width at 3 mm and 6mrn level from alveolarcrest decreased by 0.71 mm and 0.39 mm.In non-graft group,the alveolar width at 3 mm,6 mm and 9 mm level from alveolarcrest decreased by 4.1 mm,2.4 mm and 1.1 mm.Paired t-test showed significant changes (P＜0.01).The alveolar height in non-graft group reduced by 1.72 rnm,the difference is significant (P＜0.01),while graft group has no significant difference.Conclusions For orthodontic patients with mandibular first molar extraction plan,imeediatebone grafting after extraction can delaythe resorption of the alveolar bone crest,facilitating long-distance space closure. Key words: Mandibular first molar; Immediate bone grafting; alveolar bone height maintenance; Cone beam CT