Maxillary sinus lift is a bone augmentation procedure in the sinus that improves the alveolar crest height in atrophic posterior maxilla by forming new bone in the space created under the elevated sinus membrane. To date, numerous grafting materials have been used as a scaffold for new bone regeneration, including autogenous bone, bone graft substitutes, or their combination [1, 2]. Autogenous bone graft is considered as gold standard among these grafting materials; however, its limitations include morbidity of donor sites, delay of new bone generation, and complications such as material infection and sinusitis [3, 4].

Recent studies have shown that sinus lift by elevating the sinus membrane without grafting materials induces bone formation in the maxillary sinus [5–8]. Nongrafted sinus lift has been accepted as a predictable bone augmentation procedure in atrophic posterior maxilla. In the sinus lift procedure, bone graft and dental implants serve as space holders under the elevated sinus membrane, and new bone is formed in a secluded space under the elevated sinus membrane, according to the principle of guided tissue regeneration [5]. However, positive intra-sinus air pressure associated with respiration exists in the maxillary sinus [9], and this pressure may have a negative effect on bone formation in the sinus, thus inducing bone resorption and pneumatization after sinus augmentation [10]. Indeed, postoperative vertical bone loss is commonly observed in conventional sinus lift with autogenous bone grafting. Several years after surgery, most grafting materials covering the implant apex get resorbed, and the implant apex is exposed to the grafted sinus floor [11]. Therefore, even the presence of physiological stimuli after implant loading may alter the augmented bone volume surrounding implants in the sinus. It is difficult to maintain postoperative augmented space stable for long term, with or without grafting materials.

This article describes a case of nongrafted maxillary sinus lift using a mesh plate device consisting of bioresorbable unsintered hydroxyapatite combined with poly l-lactide (HA/PLLA) materials and dental implant placement in an atrophic posterior maxilla. In this case, continuous bone formation in the sinus was observed during the postoperative follow-up period of 3 years, and we show the sequential radiographic outcome of this procedure.