Examination of ß-TCP/collagen composite in bone defects without periosteum in dogs: a histological and cast model evaluation.

After tooth extraction, the alveolar ridge is absorbed and changes shape. Recently, socket preservation has been proposed to prevent alveolar ridge absorption. However, there are few reports of socket preservation in a model without the periosteum, and alveolar bone regeneration and resorption inhibitory effects in this type of model remain unclear. Therefore, in this study, we conducted socket preservation at the bone defect without the periosteum using a canine model. Ten beagle dogs were extracted. A 5 mm × 7 mm × 4 mm bone defect was created without the periosteum. Defects were filled with beta-tricalcium phosphate (ß-TCP)/collagen (Col), ß-TCP, collagen, or left intact (Control). The observation periods were 4 and 8 weeks (n = 5 per group). Evaluations were made of the newly formed bone area, residual granular area, horizontal width and vertical dimensional change. The newly formed bone area at 4 weeks after surgery in TCP/Col, Collagen, ß-TCP, and Control groups was 21.50%, 17.26%, 18.22%, and 17.47%. Compared to the control group, the TCP/Col group showed a significant difference in bone regeneration and horizontal width. TCP/Col is suggested to be effective for bone regeneration and suppression of alveolar ridge resorption in the bone defect periosteum removal model.

A stepwise under-prepared osteotomy technique improves primary stability in shallow-placed implants: a preliminary study for simultaneous vertical ridge augmentation.

Simultaneous vertical ridge augmentation (VRA) can reduce treatment procedures and surgery time, but the concomitant reduction in primary stability (PS) of a shallow-placed implant imparts risk to its prognosis. Although several studies have reported improvements in PS, there is little information from any simultaneous VRA model. This study aimed to evaluate whether tapered implants with stepwise under-prepared osteotomy could improve the PS of shallow-placed implants in an in vitro model of simultaneous VRA. Tapered implants (Straumann® Bone Level Tapered implant; BLT) and hybrid implants (Straumann® Bone Level implant; BL) were investigated in this study. A total of 80 osteotomies of different depths (4, 6, 8, 10 mm) were created in rigid polyurethane foam blocks, and each BLT and BL was inserted by either standard (BLT-S, BL-S) or a stepwise under-prepared (BLT-U, BL-U) osteotomy protocol. The PS was evaluated by measuring maximum insertion torque (IT), implant stability quotient (ISQ), and removal torque (RT). The significance level was set at P < 0.05. There were no significant differences in IT, ISQ or RT when comparing BLT-S and BL-S or BLT-U and BL-U at placement depths of 6 and 8 mm. When comparison was made between osteotomy protocols, IT was significantly greater in BLT-U than in BLT-S at all placement depths. A stepwise under-prepared osteotomy protocol improves initial stability of a tapered implant even in a shallow-placed implant model. BLT-U could be a useful protocol for simultaneous VRA.