Altieri Federica, Cassetta Michele
Int J Oral Maxillofac Implants. 2025 Feb 7;40(1):41-50. doi: 10.11607/jomi.10947.
To evaluate the extent of crestal bone loss (CBL) at 2, 12, 36, and 60 months in implants placed with the shoulder at the equicrestal level and 2 mm below the alveolar ridge.
A split-mouth randomized controlled clinical trial was conducted by selecting subjects with a Kennedy Class IV partially edentulous mandible. Two implants of equal length and diameter were inserted, one equicrestal and the other subcrestal, in the lateral incisor sites. Using Rinn centering devices, intraoral periapical radiographs were taken at implant insertion (T0) and at 2 (T1), 12 (T2), 36 (T3), and 60 months (T4). Descriptive statistics and t test were used, with P ≤ .05 considered statistically significant. Twentyfive patients were recruited, with a mean age of 65 ± 9.88 years (range: 42 to 82 years), and none dropped out. A total of 50 implants were inserted, 25 at the crestal level and 25 at the subcrestal level.
At the 60-month follow-up, no implant or prosthetic failure was recorded. An average CBL of 0.81 ± 0.40 mm (range: 0.1 to 1.6 mm) was recorded in the crestal implant group, while the subcrestal implants had an average CBL of 0.87 ± 0.41 mm (range: 0.2 to 2 mm); however, the higher CBL in the subcrestal group was not statistically significant (P = .65). Comparing the mean CBL of both groups at the various follow-ups, greater crestal bone resorption was recorded in subcrestal implants between T0 and T1 (0.25 vs 0.1 mm) and between T1 and T2 (0.39 vs 0.23 mm), while in subsequent follow-ups, a greater and statistically significant (P = .01) CBL was recorded in equicrestal implants between T3 and T4 (0.05 vs 0.18 mm).
Thus, over time, the extent of CBL seems to be reduced in subcrestal implants, with bone retention above the implant shoulder. Although the position of the implant shoulder relative to the crestal ridge does not affect the CBL, subcrestal placement is recommended in order to reduce the risk of exposing the rough implant surface.
评估种植体肩部位于牙槽嵴顶水平及牙槽嵴顶以下2mm处时，在2个月、12个月、36个月和60个月时嵴顶骨吸收（CBL）的程度。
选取患有肯尼迪IV类部分牙列缺失下颌骨的受试者进行一项口内分区随机对照临床试验。在侧切牙部位植入两颗长度和直径相同的种植体，一颗位于牙槽嵴顶水平，另一颗位于牙槽嵴顶以下。使用林恩定位装置，在种植体植入时（T0）以及2个月（T1）、12个月（T2）、36个月（T3）和60个月（T4）时拍摄口内根尖片。采用描述性统计和t检验，P≤0.05被认为具有统计学意义。招募了25名患者，平均年龄为65±9.88岁（范围：42至82岁），无患者退出。共植入50颗种植体，25颗位于牙槽嵴顶水平，25颗位于牙槽嵴顶以下水平。
在60个月的随访中，未记录到种植体或修复体失败。牙槽嵴顶种植体组的平均CBL为0.81±0.40mm（范围：0.1至1.6mm），而牙槽嵴顶以下种植体的平均CBL为0.87±0.41mm（范围：0.2至2mm）；然而，牙槽嵴顶以下种植体组较高的CBL无统计学意义（P = 0.65）。比较两组在不同随访时间的平均CBL，牙槽嵴顶以下种植体在T0至T1（0.25对0.1mm）和T1至T2（0.39对0.23mm）期间记录到更大的牙槽嵴顶骨吸收，而在随后的随访中，牙槽嵴顶种植体在T3至T4期间记录到更大且具有统计学意义（P = 0.01）的CBL（0.05对0.18mm）。
因此，随着时间的推移，牙槽嵴顶以下种植体的CBL程度似乎有所降低，种植体肩部上方有骨留存。虽然种植体肩部相对于牙槽嵴顶的位置不影响CBL，但为降低暴露种植体粗糙表面的风险，建议采用牙槽嵴顶以下种植体植入方式。
