Covani Ugo, Cornelini Roberto, Calvo-Guirado Jose Louis, Tonelli Paolo, Barone Antonio
Department of Surgery, University of Pisa, Pisa, Italy.
Int J Periodontics Restorative Dent. 2010 Dec;30(6):601-7.
The aim of the present experimental study was to evaluate the physiologic bone remodeling in beagle dogs following the placement of small-diameter (3.25 mm) implants in fresh extraction sites. Five 1-year-old beagle dogs that weighed approximately 10 to 13 kg each were used in this study. The third and fourth premolars (P3, P4) were used as experimental teeth, which were hemisected using a fissure bur; the distal roots were removed carefully using forceps. Implants (3.25-mm wide, 10- or 11.5-mm long) were placed in the fresh extraction sockets with the neck of the implant at the level of the buccal bone crest. The dogs were subsequently put to sleep according to the following schedule: one dog 15 days after implant placement, two dogs after 1 month, and the remaining two dogs after 3 months. The distance from the implant shoulder to the bone wall crest was measured at both the buccal and lingual sites. The width of the buccolingual bone crest was measured using a caliper. Assessments were made immediately after root extraction and at 2, 4, and 12 weeks after implant placement. The mean width of the buccolingual bone crest was 4.5 ± 0.5 mm at the time of root extraction. Subsequently, at 2, 4, and 12 weeks after implant placement, the buccolingual bone width was 4.1 ± 0.5 mm, 3.7 ± 0.3 mm, and 3.5 ± 0.7 mm, respectively. Two weeks after implant placement, the lingual bone crest was measured at 0.2 ± 0.3 mm from the implant shoulder, while the buccal bone crest was 0.3 ± 0.3 mm. After 4 weeks of healing, the mean distance from the implant shoulder to the lingual bone crest was 0.1 ± 0.9 mm, compared to 0.4 ± 0.9 mm for the buccal bone crest. After 12 weeks of healing, the bone crest at the lingual sites was -0.3 ± 0.5 mm from the implant shoulder, compared to 0.8 ± 0.3 mm at the buccal sites. The findings from this study show that although vertical bone remodeling was indeed observed, the mean vertical buccal bone resorption was 0.5 mm. It might be suggested, therefore, that the implant position along the lingual wall and the use of implants with a narrow diameter in relation to the extraction socket width play a key role in reducing the rate of vertical bone resorption at the buccal aspect of implants placed in fresh extraction sockets.
本实验研究的目的是评估在比格犬新鲜拔牙位点植入小直径（3.25毫米）种植体后的生理性骨重塑情况。本研究使用了5只1岁的比格犬，每只体重约10至13千克。第三和第四前磨牙（P3、P4）用作实验牙齿，使用裂钻将其对半切开；用镊子小心地拔除远中根。将种植体（宽3.25毫米，长10或11.5毫米）植入新鲜拔牙窝，种植体颈部位于颊侧牙槽嵴水平。随后，按照以下时间表对犬实施安乐死：1只犬在植入种植体后15天，2只犬在1个月后，其余2只犬在3个月后。在颊侧和舌侧位点测量种植体肩部至牙槽嵴顶的距离。使用卡尺测量颊舌向牙槽嵴顶的宽度。在牙根拔除后以及植入种植体后2周、4周和12周进行评估。牙根拔除时颊舌向牙槽嵴顶的平均宽度为4.5±0.5毫米。随后，在植入种植体后2周、4周和12周，颊舌向骨宽度分别为4.1±0.5毫米、3.7±0.3毫米和3.5±0.7毫米。植入种植体2周后，舌侧牙槽嵴顶距种植体肩部0.2±0.3毫米，而颊侧牙槽嵴顶为0.3±0.3毫米。愈合4周后，种植体肩部至舌侧牙槽嵴顶的平均距离为0.1±0.9毫米，颊侧牙槽嵴顶为0.4±0.9毫米。愈合12周后，舌侧位点的牙槽嵴顶距种植体肩部-0.3±0.5毫米，颊侧位点为0.8±0.3毫米。本研究结果表明，虽然确实观察到了垂直骨重塑，但颊侧垂直骨吸收的平均值为0.5毫米。因此，可能有人认为，种植体沿舌侧壁的位置以及相对于拔牙窝宽度使用窄直径种植体，对于降低植入新鲜拔牙窝的种植体颊侧垂直骨吸收速率起着关键作用。
